diff --git a/examples/dae/ReactionKinetics.py b/examples/dae/ReactionKinetics.py
index 0786a19e2c8..2276555a5e2 100644
--- a/examples/dae/ReactionKinetics.py
+++ b/examples/dae/ReactionKinetics.py
@@ -28,7 +28,7 @@
 solver = pyo.SolverFactory('ipopt')
 
 
-class Reaction(object):
+class Reaction:
     """A simple class to hold the stoichiometry of a single reaction
 
     Reaction data is stored in two dictionaries:
@@ -84,7 +84,7 @@ def _parseTerm(self, x):
         return coef, species.strip()
 
 
-class ReactionNetwork(object):
+class ReactionNetwork:
     """A simple object to hold sets of reactions."""
 
     def __init__(self):
diff --git a/examples/pyomo/p-median/solver1.py b/examples/pyomo/p-median/solver1.py
index 7d63400aded..bc147b54994 100644
--- a/examples/pyomo/p-median/solver1.py
+++ b/examples/pyomo/p-median/solver1.py
@@ -17,7 +17,7 @@
 
 
 @plugin_factory(pyo.SolverFactory)
-class MySolver(object):
+class MySolver:
     alias('greedy')
 
     # Declare that this is an IOptSolver plugin
diff --git a/examples/pyomo/p-median/solver2.py b/examples/pyomo/p-median/solver2.py
index f8355d34b23..6b64e1cc078 100644
--- a/examples/pyomo/p-median/solver2.py
+++ b/examples/pyomo/p-median/solver2.py
@@ -18,7 +18,7 @@
 
 
 @plugin_factory
-class MySolver(object):
+class MySolver:
     alias('random')
 
     # Declare that this is an IOptSolver plugin
diff --git a/pyomo/common/autoslots.py b/pyomo/common/autoslots.py
index 3b5b3b00154..e563544c50e 100644
--- a/pyomo/common/autoslots.py
+++ b/pyomo/common/autoslots.py
@@ -276,7 +276,7 @@ def encode_as_none(encode, val):
         else:
             return val
 
-    class Mixin(object):
+    class Mixin:
         """Mixin class to configure a class hierarchy to use AutoSlots
 
         Inheriting from this class will set up the automatic generation
diff --git a/pyomo/common/config.py b/pyomo/common/config.py
index 806501d7df9..d012598e000 100644
--- a/pyomo/common/config.py
+++ b/pyomo/common/config.py
@@ -204,7 +204,7 @@ def NonNegativeFloat(val):
     return ans
 
 
-class In(object):
+class In:
     """In(domain, cast=None)
     Domain validation class admitting a Container of possible values
 
@@ -268,7 +268,7 @@ def domain_name(self):
             return f'In{_dn}'
 
 
-class InEnum(object):
+class InEnum:
     """Domain validation class admitting an enum value/name.
 
     This will admit any value that is in the specified Enum, including
@@ -301,7 +301,7 @@ def domain_name(self):
         return f'InEnum[{_domain_name(self._domain)}]'
 
 
-class IsInstance(object):
+class IsInstance:
     """
     Domain validator for type checking.
 
@@ -365,7 +365,7 @@ def domain_name(self):
         return f"IsInstance[{', '.join(class_names)}]"
 
 
-class ListOf(object):
+class ListOf:
     """Domain validator for lists of a specified type
 
     Parameters
@@ -411,7 +411,7 @@ def domain_name(self):
         return f'ListOf[{_dn}]'
 
 
-class Module(object):
+class Module:
     """Domain validator for modules.
 
     Modules can be specified as module objects, by module name,
@@ -485,7 +485,7 @@ def __call__(self, module_id):
         return import_file(path)
 
 
-class Path(object):
+class Path:
     """
     Domain validator for a
     :py:term:`path-like object <path-like object>`.
@@ -594,7 +594,7 @@ def __call__(self, data):
             return [super(PathList, self).__call__(data)]
 
 
-class DynamicImplicitDomain(object):
+class DynamicImplicitDomain:
     """Implicit domain that can return a custom domain based on the key.
 
     This provides a mechanism for managing plugin-like systems, where
@@ -810,7 +810,7 @@ def from_enum_or_string(cls, arg):
 
 .. doctest::
 
-    >>> class Base(object):
+    >>> class Base:
     ...     CONFIG = ConfigDict()
     ...     CONFIG.declare('filename', ConfigValue(
     ...         default='input.txt',
@@ -854,7 +854,7 @@ class will still create ``c`` instances that only have the single
 
 .. doctest::
 
-    >>> class Solver(object):
+    >>> class Solver:
     ...     CONFIG = ConfigDict()
     ...     CONFIG.declare('iterlim', ConfigValue(
     ...         default=10,
@@ -1211,7 +1211,7 @@ def _value2yaml(prefix, value, obj):
     return _str.rstrip()
 
 
-class _UnpickleableDomain(object):
+class _UnpickleableDomain:
     def __init__(self, obj):
         self._type = type(obj).__name__
         self._name = obj.name(True)
@@ -1410,7 +1410,7 @@ def _item_body_cb(self, indent, obj):
     return types.MethodType(_item_body_cb, formatter)
 
 
-class ConfigFormatter(object):
+class ConfigFormatter:
     def _initialize(self, indent_spacing, width, visibility):
         self.out = io.StringIO()
         self.indent_spacing = indent_spacing
@@ -1565,7 +1565,7 @@ def add_docstring_list(docstring, configdict, indent_by=4):
     )
 
 
-class document_kwargs_from_configdict(object):
+class document_kwargs_from_configdict:
     """Decorator to append the documentation of a ConfigDict to the docstring
 
     This adds the documentation of the specified :py:class:`ConfigDict`
@@ -1600,7 +1600,7 @@ class document_kwargs_from_configdict(object):
     >>> from pyomo.common.config import (
     ...     ConfigDict, ConfigValue, document_kwargs_from_configdict
     ... )
-    >>> class MyClass(object):
+    >>> class MyClass:
     ...     CONFIG = ConfigDict()
     ...     CONFIG.declare('iterlim', ConfigValue(
     ...         default=3000,
@@ -1676,7 +1676,7 @@ def __call__(self, fcn):
         return fcn
 
 
-class UninitializedMixin(object):
+class UninitializedMixin:
     """Mixin class to support delayed data initialization.
 
     This mixin can be used to create a derived Config class that hides
@@ -1743,7 +1743,7 @@ def _data(self, value):
         self._data = value
 
 
-class ConfigBase(object):
+class ConfigBase:
     # Note: __getstate__ relies on this field ordering.  Do not change.
     __slots__ = (
         '_parent',
@@ -1763,7 +1763,7 @@ class ConfigBase(object):
     # we can tell if an argument is provided (and we can't use None as
     # None is a valid user-specified argument).  Making it a class helps
     # when Config objects are pickled.
-    class NoArgument(object):
+    class NoArgument:
         pass
 
     def __init__(
@@ -2293,7 +2293,7 @@ def _setter(self, value):
             self._data = _data
 
 
-class MarkImmutable(object):
+class MarkImmutable:
     """
     Mark instances of ConfigValue as immutable.
 
diff --git a/pyomo/common/dependencies.py b/pyomo/common/dependencies.py
index efd47bf2deb..49114c2c0bb 100644
--- a/pyomo/common/dependencies.py
+++ b/pyomo/common/dependencies.py
@@ -31,7 +31,7 @@
 SUPPRESS_DEPENDENCY_WARNINGS = False
 
 
-class ModuleUnavailable(object):
+class ModuleUnavailable:
     """Mock object that raises :py:class:`.DeferredImportError` upon attribute access
 
     This object is returned by :py:func:`attempt_import()` in lieu of
@@ -129,7 +129,7 @@ def generate_import_warning(self, logger='pyomo.common'):
         self.log_import_warning(logger)
 
 
-class DeferredImportModule(object):
+class DeferredImportModule:
     """Mock module object to support the deferred import of a module.
 
     This object is returned by :py:func:`attempt_import()` in lieu of
@@ -281,7 +281,7 @@ def __new__(cls, *args, **kwargs):
     return UnavailableBase
 
 
-class _DeferredImportIndicatorBase(object):
+class _DeferredImportIndicatorBase:
     def __and__(self, other):
         return _DeferredAnd(self, other)
 
@@ -857,7 +857,7 @@ def declare_deferred_modules_as_importable(globals_dict):
     return declare_modules_as_importable(globals_dict).__exit__(None, None, None)
 
 
-class declare_modules_as_importable(object):
+class declare_modules_as_importable:
     """Make all :py:class:`ModuleType` and :py:class:`DeferredImportModules`
     importable through the ``globals_dict`` context.
 
diff --git a/pyomo/common/deprecation.py b/pyomo/common/deprecation.py
index 4f34043d713..a82468a3ede 100644
--- a/pyomo/common/deprecation.py
+++ b/pyomo/common/deprecation.py
@@ -469,7 +469,7 @@ class RenamedClass(type):
     Examples
     --------
     >>> from pyomo.common.deprecation import RenamedClass
-    >>> class NewClass(object):
+    >>> class NewClass:
     ...     pass
     >>> class OldClass(metaclass=RenamedClass):
     ...     __renamed__new_class__ = NewClass
diff --git a/pyomo/common/download.py b/pyomo/common/download.py
index 073ac6f9dad..4c457f9221e 100644
--- a/pyomo/common/download.py
+++ b/pyomo/common/download.py
@@ -38,7 +38,7 @@
 DownloadFactory = pyomo.common.Factory('library downloaders')
 
 
-class FileDownloader(object):
+class FileDownloader:
     _os_version = None
 
     def __init__(self, insecure=False, cacert=None):
diff --git a/pyomo/common/env.py b/pyomo/common/env.py
index d372b061e51..33551f99139 100644
--- a/pyomo/common/env.py
+++ b/pyomo/common/env.py
@@ -99,7 +99,7 @@ def _load_dll(name, timeout=10):
 _load_dll.pool = None
 
 
-class _RestorableEnvironInterface(object):
+class _RestorableEnvironInterface:
     """Interface to track environment changes and restore state"""
 
     def __init__(self, dll):
@@ -160,7 +160,7 @@ def __delitem__(self, key):
             self.dll.putenv_s(key, b'')
 
 
-class _OSEnviron(object):
+class _OSEnviron:
     """Helper class to proxy a "DLL-like" interface to os.environ"""
 
     _libname = 'os.environ'
@@ -205,7 +205,7 @@ def wputenv_s(self, key, val):
         os.environ[key] = val
 
 
-class _MsvcrtDLL(object):
+class _MsvcrtDLL:
     """Helper class to manage the interface with the MSVCRT runtime"""
 
     def __init__(self, name):
@@ -280,7 +280,7 @@ def get_env_dict(self):
         return ans
 
 
-class _Win32DLL(object):
+class _Win32DLL:
     """Helper class to manage the interface with the Win32 runtime"""
 
     def __init__(self, name):
@@ -381,7 +381,7 @@ def get_env_dict(self):
         return ans
 
 
-class CtypesEnviron(object):
+class CtypesEnviron:
     """A context manager for managing environment variables
 
     This class provides a simplified interface for consistently setting
diff --git a/pyomo/common/factory.py b/pyomo/common/factory.py
index e1cb8543f74..1c744d378fd 100644
--- a/pyomo/common/factory.py
+++ b/pyomo/common/factory.py
@@ -17,7 +17,7 @@
 #  ___________________________________________________________________________
 
 
-class Factory(object):
+class Factory:
     """
     A class that is used to define a factory for objects.
 
diff --git a/pyomo/common/fileutils.py b/pyomo/common/fileutils.py
index 4a0b2beb36b..8e706bf4232 100644
--- a/pyomo/common/fileutils.py
+++ b/pyomo/common/fileutils.py
@@ -505,7 +505,7 @@ def import_file(path, clear_cache=False, infer_package=True, module_name=None):
     return module
 
 
-class PathData(object):
+class PathData:
     """An object for storing and managing a :py:class:`PathManager` path"""
 
     def __init__(self, manager, name):
@@ -610,7 +610,7 @@ def executable(self, value):
         self.set_path(value)
 
 
-class PathManager(object):
+class PathManager:
     """The PathManager defines a registry class for path locations
 
     The :py:class:`PathManager` defines a class very similar to the
diff --git a/pyomo/common/formatting.py b/pyomo/common/formatting.py
index 71798565417..710116a98fe 100644
--- a/pyomo/common/formatting.py
+++ b/pyomo/common/formatting.py
@@ -196,7 +196,7 @@ def tabular_writer(ostream, prefix, data, header, row_generator):
             )
 
 
-class StreamIndenter(object):
+class StreamIndenter:
     """
     Mock-up of a file-like object that wraps another file-like object
     and indents all data using the specified string before passing it to
diff --git a/pyomo/common/gc_manager.py b/pyomo/common/gc_manager.py
index 5745fe1a97e..5610002b871 100644
--- a/pyomo/common/gc_manager.py
+++ b/pyomo/common/gc_manager.py
@@ -20,7 +20,7 @@
 from pyomo.common.multithread import MultiThreadWrapper
 
 
-class __PauseGCCompanion(object):
+class __PauseGCCompanion:
     def __init__(self):
         self._stack_depth = 0
 
@@ -41,7 +41,7 @@ def __init__(self):
 # the GC will be re-enabled (if it was not initially disabled).  It is
 # safe to nest instances of PauseGC That is, you don't have to worry
 # if an outer function/method has its own instance of PauseGC.
-class PauseGC(object):
+class PauseGC:
     __slots__ = ("reenable_gc", "stack_pointer")
 
     def __init__(self):
diff --git a/pyomo/common/log.py b/pyomo/common/log.py
index 3e2b77729f7..b459cf9c43f 100644
--- a/pyomo/common/log.py
+++ b/pyomo/common/log.py
@@ -237,7 +237,7 @@ def emit(self, record):
             self.stream = orig
 
 
-class Preformatted(object):
+class Preformatted:
     __slots__ = ('msg',)
 
     def __init__(self, msg):
@@ -250,7 +250,7 @@ def __repr__(self):
         return f'Preformatted({self.msg!r})'
 
 
-class _GlobalLogFilter(object):
+class _GlobalLogFilter:
     def __init__(self):
         self.logger = logging.getLogger()
 
@@ -292,7 +292,7 @@ def __init__(self, base='', stream=None, level=logging.NOTSET, verbosity=None):
         self.setFormatter(LegacyPyomoFormatter(base=base, verbosity=verbosity))
 
 
-class LoggingIntercept(object):
+class LoggingIntercept:
     r"""Context manager for intercepting messages sent to a log stream
 
     This class is designed to enable easy testing of log messages.
@@ -461,7 +461,7 @@ def redirect_streams(self, redirects):
                 yield _LastResortRedirector(redirects[fd].original_fd)
 
 
-class _StreamRedirector(object):
+class _StreamRedirector:
     def __init__(self, handler, fd):
         self.handler = handler
         self.fd = fd
@@ -488,7 +488,7 @@ def __exit__(self, et, ev, tb):
             self.handler.stream = self.orig_stream
 
 
-class _LastResortRedirector(object):
+class _LastResortRedirector:
     def __init__(self, fd):
         self.fd = fd
         self.local_fd = None
diff --git a/pyomo/common/plugin_base.py b/pyomo/common/plugin_base.py
index f33bff09026..a54a762b6bf 100644
--- a/pyomo/common/plugin_base.py
+++ b/pyomo/common/plugin_base.py
@@ -23,7 +23,7 @@
 from pyomo.common.deprecation import deprecated, deprecation_warning
 
 
-class PluginGlobals(object):
+class PluginGlobals:
     @staticmethod
     @deprecated(
         "The PluginGlobals environment manager is deprecated: "
@@ -254,7 +254,7 @@ class SingletonPlugin(Plugin):
     __singleton__ = True
 
 
-class ExtensionPoint(object):
+class ExtensionPoint:
     def __init__(self, interface):
         assert issubclass(interface, Interface)
         self._interface = interface
@@ -302,7 +302,7 @@ def service(self, key=None, all=False):
             )
 
 
-class PluginFactory(object):
+class PluginFactory:
     def __init__(self, interface):
         self.interface = interface
 
diff --git a/pyomo/common/sorting.py b/pyomo/common/sorting.py
index bb5ea13f55e..65b7dee505a 100644
--- a/pyomo/common/sorting.py
+++ b/pyomo/common/sorting.py
@@ -10,7 +10,7 @@
 #  ___________________________________________________________________________
 
 
-class _robust_sort_keyfcn(object):
+class _robust_sort_keyfcn:
     """Class for robustly generating sortable keys for arbitrary data.
 
     Generates keys (for use with Python `sorted()` that are
diff --git a/pyomo/common/tee.py b/pyomo/common/tee.py
index 6cc986a1bc5..a5b35e02dd5 100644
--- a/pyomo/common/tee.py
+++ b/pyomo/common/tee.py
@@ -54,7 +54,7 @@
 logger = logging.getLogger(__name__)
 
 
-class _SignalFlush(object):
+class _SignalFlush:
     def __init__(self, ostream, handle):
         super().__setattr__('_ostream', ostream)
         super().__setattr__('_handle', handle)
@@ -80,7 +80,7 @@ def writelines(self, data):
         self.flush()
 
 
-class _fd_closer(object):
+class _fd_closer:
     """A context manager to handle closing a specified file descriptor
 
     Ideally we would use `os.fdopen(... closefd=True)`; however, it
@@ -101,7 +101,7 @@ def __exit__(self, et, ev, tb):
         os.close(self.fd)
 
 
-class redirect_fd(object):
+class redirect_fd:
     """Redirect a file descriptor to a new file or file descriptor.
 
     This context manager will redirect the specified file descriptor to
@@ -189,7 +189,7 @@ def __exit__(self, et, ev, tb):
         os.close(self.original_fd)
 
 
-class capture_output(object):
+class capture_output:
     """Context manager to capture output sent to sys.stdout and sys.stderr
 
     This is a drop-in substitute for PyUtilib's capture_output to
@@ -475,7 +475,7 @@ def reset(self):
         return self.__exit__(None, None, None)
 
 
-class _StreamHandle(object):
+class _StreamHandle:
     """A stream handler object used by TeeStream
 
     This handler holds the two sides of the pipe used to communicate
@@ -643,7 +643,7 @@ def writeOutputBuffer(self, ostreams, flush):
                 )
 
 
-class TeeStream(object):
+class TeeStream:
     def __init__(self, *ostreams, encoding=None, buffering=-1):
         self.ostreams = ostreams
         self.encoding = encoding
diff --git a/pyomo/common/tempfiles.py b/pyomo/common/tempfiles.py
index 7d8c81cd641..e61802065b7 100644
--- a/pyomo/common/tempfiles.py
+++ b/pyomo/common/tempfiles.py
@@ -33,7 +33,7 @@
 pyutilib_tempfiles, _ = attempt_import('pyutilib.component.config.tempfiles')
 
 
-class TempfileManagerClass(object):
+class TempfileManagerClass:
     """A class for managing tempfile contexts
 
     Pyomo declares a global instance of this class as ``TempfileManager``:
diff --git a/pyomo/common/tests/mod.py b/pyomo/common/tests/mod.py
index 495aae457df..6c637fb5fd8 100644
--- a/pyomo/common/tests/mod.py
+++ b/pyomo/common/tests/mod.py
@@ -13,5 +13,5 @@
 # This is a simple module used as part of testing import callbacks
 
 
-class Foo(object):
+class Foo:
     data = 42
diff --git a/pyomo/common/tests/moved.py b/pyomo/common/tests/moved.py
index 55912a76213..76e15cf1627 100644
--- a/pyomo/common/tests/moved.py
+++ b/pyomo/common/tests/moved.py
@@ -13,5 +13,5 @@
 # This is a simple module used as part of testing moved_module()
 
 
-class Bar(object):
+class Bar:
     data = 42
diff --git a/pyomo/common/tests/relo_mod_new.py b/pyomo/common/tests/relo_mod_new.py
index d616574aa99..86a8df83055 100644
--- a/pyomo/common/tests/relo_mod_new.py
+++ b/pyomo/common/tests/relo_mod_new.py
@@ -12,5 +12,5 @@
 RELO_ATTR = 42
 
 
-class ReloClass(object):
+class ReloClass:
     pass
diff --git a/pyomo/common/tests/relocated.py b/pyomo/common/tests/relocated.py
index b7572f7db36..3a86337088d 100644
--- a/pyomo/common/tests/relocated.py
+++ b/pyomo/common/tests/relocated.py
@@ -13,7 +13,7 @@
 from pyomo.common.deprecation import relocated_module_attribute
 
 
-class Bar(object):
+class Bar:
     data = 42
 
 
diff --git a/pyomo/common/tests/test_config.py b/pyomo/common/tests/test_config.py
index da87e5fe340..dc14284121a 100644
--- a/pyomo/common/tests/test_config.py
+++ b/pyomo/common/tests/test_config.py
@@ -86,7 +86,7 @@ def _display(obj, *args):
     return test.getvalue()
 
 
-class GlobalClass(object):
+class GlobalClass:
     "test class for test_known_types"
 
     pass
@@ -409,7 +409,7 @@ def test_In(self):
         c.b = '1'
         self.assertEqual(c.b, 1)
 
-        class Container(object):
+        class Container:
             def __init__(self, vals):
                 self._vals = vals
 
@@ -1427,7 +1427,7 @@ def test_display_userdata_add_block_nonDefault(self):
         )
 
     def test_display_nondata_type(self):
-        class NOOP(object):
+        class NOOP:
             def __getattr__(self, attr):
                 def noop(*args, **kwargs):
                     pass
@@ -2898,7 +2898,7 @@ def test_call_options(self):
         self.assertEqual(mod_copy._visibility, 0)
 
     def test_template_nondata(self):
-        class NOOP(object):
+        class NOOP:
             def __getattr__(self, attr):
                 def noop(*args, **kwargs):
                     pass
@@ -3014,7 +3014,7 @@ def local_fcn():
 
     def test_known_types(self):
         def local_fcn():
-            class LocalClass(object):
+            class LocalClass:
                 pass
 
             return LocalClass
@@ -3097,7 +3097,7 @@ def test_declare_from(self):
 
     def test_docstring_decorator(self):
         @document_kwargs_from_configdict('CONFIG')
-        class ExampleClass(object):
+        class ExampleClass:
             CONFIG = ExampleConfig()
 
             @document_kwargs_from_configdict(CONFIG)
@@ -3302,7 +3302,7 @@ def domain_name(self):
         self.assertEqual(cfg.get('type').domain_name(), 'int')
 
     def test_deferred_initialization(self):
-        class Accumulator(object):
+        class Accumulator:
             def __init__(self):
                 self.data = []
 
diff --git a/pyomo/common/tests/test_dependencies.py b/pyomo/common/tests/test_dependencies.py
index 2669be4cd12..6aa41c0d89b 100644
--- a/pyomo/common/tests/test_dependencies.py
+++ b/pyomo/common/tests/test_dependencies.py
@@ -265,7 +265,7 @@ def test_callback_on_import(self):
         sys.modules.pop('pyomo.common.tests.mod', None)
         ans = []
 
-        class ImpFinder(object):
+        class ImpFinder:
             # This is an "imp" module-style finder (deprecated in Python
             # 3.4 and removed in Python 3.12, but Google Collab still
             # defines finders like this)
diff --git a/pyomo/common/tests/test_deprecated.py b/pyomo/common/tests/test_deprecated.py
index a44f9058a5e..0daefcbdd1a 100644
--- a/pyomo/common/tests/test_deprecated.py
+++ b/pyomo/common/tests/test_deprecated.py
@@ -74,13 +74,13 @@ def foo():
         ):
 
             @deprecated()
-            class foo(object):
+            class foo:
                 pass
 
         # But no exception if the class can infer a version from the
         # __init__ (or __new__ or __new_member__)
         @deprecated()
-        class foo(object):
+        class foo:
             @deprecated(version="1.2")
             def __init__(self):
                 pass
@@ -258,7 +258,7 @@ def foo(bar='yeah'):
 
     def test_with_class(self):
         @deprecated(version='test')
-        class foo(object):
+        class foo:
             def __init__(self):
                 logger.warning('yeah')
 
@@ -285,7 +285,7 @@ def __init__(self):
         )
 
     def test_with_method(self):
-        class foo(object):
+        class foo:
             def __init__(self):
                 pass
 
@@ -316,7 +316,7 @@ def bar(self):
         )
 
     def test_with_remove_in(self):
-        class foo(object):
+        class foo:
             def __init__(self):
                 pass
 
@@ -348,7 +348,7 @@ def bar(self):
         )
 
 
-class Bar(object):
+class Bar:
     data = 21
 
 
@@ -498,7 +498,7 @@ def test_relocated_module(self):
 
 class TestRenamedClass(unittest.TestCase):
     def test_renamed(self):
-        class NewClass(object):
+        class NewClass:
             attr = 'NewClass'
 
         class NewClassSubclass(NewClass):
@@ -640,7 +640,7 @@ class DeprecatedClassSubSubclass(DeprecatedClassSubclass, otherClass):
         self.assertEqual(DeprecatedClassSubSubclass.attr, 'DeprecatedClassSubSubclass')
 
     def test_renamed_errors(self):
-        class NewClass(object):
+        class NewClass:
             pass
 
         with self.assertRaisesRegex(
diff --git a/pyomo/common/tests/test_sorting.py b/pyomo/common/tests/test_sorting.py
index 5bd3c3399d8..872d08ece7c 100644
--- a/pyomo/common/tests/test_sorting.py
+++ b/pyomo/common/tests/test_sorting.py
@@ -22,7 +22,7 @@
 # The following are custom types used for testing sorted_robust.  They
 # are declared at the module scope to ensure consistent generation of
 # the class __name__.
-class LikeFloat(object):
+class LikeFloat:
     def __init__(self, n):
         self.n = n
 
@@ -33,7 +33,7 @@ def __gt__(self, other):
         return self.n > other
 
 
-class Comparable(object):
+class Comparable:
     def __init__(self, n):
         self.n = str(n)
 
@@ -44,7 +44,7 @@ def __gt__(self, other):
         return self.n > other
 
 
-class ToStr(object):
+class ToStr:
     def __init__(self, n):
         self.n = str(n)
 
@@ -52,7 +52,7 @@ def __str__(self):
         return self.n
 
 
-class NoStr(object):
+class NoStr:
     def __init__(self, n):
         self.n = str(n)
 
diff --git a/pyomo/common/tests/test_tee.py b/pyomo/common/tests/test_tee.py
index 5f3cd98719e..1fd55420991 100644
--- a/pyomo/common/tests/test_tee.py
+++ b/pyomo/common/tests/test_tee.py
@@ -666,7 +666,7 @@ def test_exit_on_del(self):
             raise
 
     def test_deadlock(self):
-        class MockStream(object):
+        class MockStream:
             def write(self, data):
                 # This test will kill the write before this sleep is
                 # done, so a long sleep won't impact suite run time.
@@ -710,7 +710,7 @@ def flush(self):
             tee._poll_timeout, tee._poll_timeout_deadlock = _save
 
 
-class BufferTester(object):
+class BufferTester:
     def setUp(self):
         sys.stdout.flush()
         sys.stderr.flush()
diff --git a/pyomo/common/timing.py b/pyomo/common/timing.py
index b08b2bd07dc..ffcbd6fa47e 100644
--- a/pyomo/common/timing.py
+++ b/pyomo/common/timing.py
@@ -44,7 +44,7 @@
 _transform_logger = logging.getLogger('pyomo.common.timing.transformation')
 
 
-class report_timing(object):
+class report_timing:
     def __init__(self, stream=True, level=logging.INFO):
         """Set reporting of Pyomo timing information.
 
@@ -99,7 +99,7 @@ def __exit__(self, et, ev, tb):
         self.reset()
 
 
-class GeneralTimer(object):
+class GeneralTimer:
     def __init__(self, fmt, data):
         self.fmt = fmt
         self.data = data
@@ -119,7 +119,7 @@ def __str__(self):
         return self.fmt % self.data
 
 
-class ConstructionTimer(object):
+class ConstructionTimer:
     __slots__ = ('obj', 'timer')
     msg = "%6.*f seconds to construct %s %s%s"
     in_progress = "ConstructionTimer object for %s %s; %0.3f elapsed seconds"
@@ -184,7 +184,7 @@ def __str__(self):
         )
 
 
-class TransformationTimer(object):
+class TransformationTimer:
     __slots__ = ('obj', 'mode', 'timer')
     msg = "%6.*f seconds to apply Transformation %s%s"
     in_progress = "TransformationTimer object for %s%s; %0.3f elapsed seconds"
@@ -233,7 +233,7 @@ def __str__(self):
 default_timer = time.perf_counter
 
 
-class TicTocTimer(object):
+class TicTocTimer:
     """A class to calculate and report elapsed time.
 
     Examples:
@@ -506,7 +506,7 @@ def _clear_timers_except(timer, to_retain):
             timer.timers.pop(key)
 
 
-class _HierarchicalHelper(object):
+class _HierarchicalHelper:
     def __init__(self):
         self.tic_toc = TicTocTimer()
         self.timers = dict()
@@ -589,7 +589,7 @@ def clear_except(self, *args):
         _clear_timers_except(self, to_retain)
 
 
-class HierarchicalTimer(object):
+class HierarchicalTimer:
     """A class for collecting and displaying hierarchical timing
     information
 
diff --git a/pyomo/common/unittest.py b/pyomo/common/unittest.py
index a332e38deee..2e6fbc33088 100644
--- a/pyomo/common/unittest.py
+++ b/pyomo/common/unittest.py
@@ -687,7 +687,7 @@ def assertExpressionsStructurallyEqual(
 )
 
 
-class BaselineTestDriver(object):
+class BaselineTestDriver:
     """Generic driver for performing baseline tests in bulk
 
     This test driver was originally crafted for testing the examples in
diff --git a/pyomo/contrib/ampl_function_demo/build.py b/pyomo/contrib/ampl_function_demo/build.py
index 10b9667aded..34ae538ce6e 100644
--- a/pyomo/contrib/ampl_function_demo/build.py
+++ b/pyomo/contrib/ampl_function_demo/build.py
@@ -23,7 +23,7 @@ def build_ampl_function_demo(user_args=[], parallel=None):
     )
 
 
-class AMPLFunctionDemoBuilder(object):
+class AMPLFunctionDemoBuilder:
     def __call__(self, parallel):
         return build_ampl_function_demo(parallel=parallel)
 
diff --git a/pyomo/contrib/appsi/base.py b/pyomo/contrib/appsi/base.py
index 0f7cfda4437..f08c295f07e 100644
--- a/pyomo/contrib/appsi/base.py
+++ b/pyomo/contrib/appsi/base.py
@@ -379,7 +379,7 @@ def get_reduced_costs(
         return rc
 
 
-class Results(object):
+class Results:
     """
     Base class for all APPSI solver results
 
@@ -1512,7 +1512,7 @@ def update(self, timer: HierarchicalTimer = None):
 }
 
 
-class LegacySolverInterface(object):
+class LegacySolverInterface:
     def solve(
         self,
         model: BlockData,
diff --git a/pyomo/contrib/appsi/build.py b/pyomo/contrib/appsi/build.py
index 3412fb9fc42..e07681ddb1a 100644
--- a/pyomo/contrib/appsi/build.py
+++ b/pyomo/contrib/appsi/build.py
@@ -108,7 +108,7 @@ def run(self):
         pybind11.setup_helpers.MACOS = original_pybind11_setup_helpers_macos
 
 
-class AppsiBuilder(object):
+class AppsiBuilder:
     def __call__(self, parallel):
         return build_appsi()
 
diff --git a/pyomo/contrib/appsi/solvers/gurobi.py b/pyomo/contrib/appsi/solvers/gurobi.py
index 6bf1d39fd5f..123aef6ae25 100644
--- a/pyomo/contrib/appsi/solvers/gurobi.py
+++ b/pyomo/contrib/appsi/solvers/gurobi.py
@@ -111,7 +111,7 @@ def __init__(self, solver):
         self.solution_loader = GurobiSolutionLoader(solver=solver)
 
 
-class _MutableLowerBound(object):
+class _MutableLowerBound:
     def __init__(self, expr):
         self.var = None
         self.expr = expr
@@ -120,7 +120,7 @@ def update(self):
         self.var.setAttr('lb', value(self.expr))
 
 
-class _MutableUpperBound(object):
+class _MutableUpperBound:
     def __init__(self, expr):
         self.var = None
         self.expr = expr
@@ -129,7 +129,7 @@ def update(self):
         self.var.setAttr('ub', value(self.expr))
 
 
-class _MutableLinearCoefficient(object):
+class _MutableLinearCoefficient:
     def __init__(self):
         self.expr = None
         self.var = None
@@ -140,7 +140,7 @@ def update(self):
         self.gurobi_model.chgCoeff(self.con, self.var, value(self.expr))
 
 
-class _MutableRangeConstant(object):
+class _MutableRangeConstant:
     def __init__(self):
         self.lhs_expr = None
         self.rhs_expr = None
@@ -156,7 +156,7 @@ def update(self):
         slack.ub = rhs_val - lhs_val
 
 
-class _MutableConstant(object):
+class _MutableConstant:
     def __init__(self):
         self.expr = None
         self.con = None
@@ -165,7 +165,7 @@ def update(self):
         self.con.rhs = value(self.expr)
 
 
-class _MutableQuadraticConstraint(object):
+class _MutableQuadraticConstraint:
     def __init__(
         self, gurobi_model, gurobi_con, constant, linear_coefs, quadratic_coefs
     ):
@@ -200,7 +200,7 @@ def get_updated_rhs(self):
         return value(self.constant.expr)
 
 
-class _MutableObjective(object):
+class _MutableObjective:
     def __init__(self, gurobi_model, constant, linear_coefs, quadratic_coefs):
         self.gurobi_model = gurobi_model
         self.constant = constant
@@ -228,7 +228,7 @@ def get_updated_expression(self):
         return gurobi_expr
 
 
-class _MutableQuadraticCoefficient(object):
+class _MutableQuadraticCoefficient:
     def __init__(self):
         self.expr = None
         self.var1 = None
diff --git a/pyomo/contrib/appsi/solvers/highs.py b/pyomo/contrib/appsi/solvers/highs.py
index ffeb8023ff2..fc9b750276e 100644
--- a/pyomo/contrib/appsi/solvers/highs.py
+++ b/pyomo/contrib/appsi/solvers/highs.py
@@ -83,7 +83,7 @@ def __init__(self, solver):
         self.solution_loader = PersistentSolutionLoader(solver=solver)
 
 
-class _MutableVarBounds(object):
+class _MutableVarBounds:
     def __init__(self, lower_expr, upper_expr, pyomo_var_id, var_map, highs):
         self.pyomo_var_id = pyomo_var_id
         self.lower_expr = lower_expr
@@ -98,7 +98,7 @@ def update(self):
         self.highs.changeColBounds(col_ndx, lb, ub)
 
 
-class _MutableLinearCoefficient(object):
+class _MutableLinearCoefficient:
     def __init__(self, pyomo_con, pyomo_var_id, con_map, var_map, expr, highs):
         self.expr = expr
         self.highs = highs
@@ -113,7 +113,7 @@ def update(self):
         self.highs.changeCoeff(row_ndx, col_ndx, value(self.expr))
 
 
-class _MutableObjectiveCoefficient(object):
+class _MutableObjectiveCoefficient:
     def __init__(self, pyomo_var_id, var_map, expr, highs):
         self.expr = expr
         self.highs = highs
@@ -125,7 +125,7 @@ def update(self):
         self.highs.changeColCost(col_ndx, value(self.expr))
 
 
-class _MutableObjectiveOffset(object):
+class _MutableObjectiveOffset:
     def __init__(self, expr, highs):
         self.expr = expr
         self.highs = highs
@@ -134,7 +134,7 @@ def update(self):
         self.highs.changeObjectiveOffset(value(self.expr))
 
 
-class _MutableConstraintBounds(object):
+class _MutableConstraintBounds:
     def __init__(self, lower_expr, upper_expr, pyomo_con, con_map, highs):
         self.lower_expr = lower_expr
         self.upper_expr = upper_expr
diff --git a/pyomo/contrib/appsi/writers/config.py b/pyomo/contrib/appsi/writers/config.py
index 8d7d3ffe6b4..0481d4bf301 100644
--- a/pyomo/contrib/appsi/writers/config.py
+++ b/pyomo/contrib/appsi/writers/config.py
@@ -10,6 +10,6 @@
 #  ___________________________________________________________________________
 
 
-class WriterConfig(object):
+class WriterConfig:
     def __init__(self):
         self.symbolic_solver_labels = False
diff --git a/pyomo/contrib/benders/examples/farmer.py b/pyomo/contrib/benders/examples/farmer.py
index d932caa4520..85e9782b519 100644
--- a/pyomo/contrib/benders/examples/farmer.py
+++ b/pyomo/contrib/benders/examples/farmer.py
@@ -25,7 +25,7 @@
 """
 
 
-class Farmer(object):
+class Farmer:
     def __init__(self):
         self.crops = ['WHEAT', 'CORN', 'SUGAR_BEETS']
         self.total_acreage = 500
diff --git a/pyomo/contrib/benders/tests/test_benders.py b/pyomo/contrib/benders/tests/test_benders.py
index 9e45f383959..86170ed6de9 100644
--- a/pyomo/contrib/benders/tests/test_benders.py
+++ b/pyomo/contrib/benders/tests/test_benders.py
@@ -29,7 +29,7 @@ class MPITestBenders(unittest.TestCase):
     @unittest.skipIf(not numpy_available, 'numpy is not available.')
     @unittest.skipIf(not mip_available, 'MIP solver is not available.')
     def test_farmer(self):
-        class Farmer(object):
+        class Farmer:
             def __init__(self):
                 self.crops = ['WHEAT', 'CORN', 'SUGAR_BEETS']
                 self.total_acreage = 500
@@ -252,7 +252,7 @@ def create_subproblem(root):
     @unittest.skipIf(not numpy_available, 'numpy is not available.')
     @unittest.skipIf(not mip_available, 'MIP solver is not available.')
     def test_four_scen_farmer(self):
-        class FourScenFarmer(object):
+        class FourScenFarmer:
             def __init__(self):
                 self.crops = ['WHEAT', 'CORN', 'SUGAR_BEETS']
                 self.total_acreage = 500
diff --git a/pyomo/contrib/community_detection/detection.py b/pyomo/contrib/community_detection/detection.py
index b81e5927407..ef6bb3af77b 100644
--- a/pyomo/contrib/community_detection/detection.py
+++ b/pyomo/contrib/community_detection/detection.py
@@ -282,7 +282,7 @@ def detect_communities(
     )
 
 
-class CommunityMap(object):
+class CommunityMap:
     """
     This class is used to create CommunityMap objects which are returned by the detect_communities function. Instances
     of this class allow dict-like usage and store relevant information about the given community map, such as the
diff --git a/pyomo/contrib/cp/repn/docplex_writer.py b/pyomo/contrib/cp/repn/docplex_writer.py
index c8ef259f847..b115af48f37 100644
--- a/pyomo/contrib/cp/repn/docplex_writer.py
+++ b/pyomo/contrib/cp/repn/docplex_writer.py
@@ -127,65 +127,65 @@ def _finalize_docplex(module, available):
 
 
 # These are things that don't need special handling:
-class _GENERAL(object):
+class _GENERAL:
     pass
 
 
 # These are operations that need to be deferred sometimes, usually because of
 # indirection:
-class _START_TIME(object):
+class _START_TIME:
     pass
 
 
-class _END_TIME(object):
+class _END_TIME:
     pass
 
 
-class _DEFERRED_ELEMENT_CONSTRAINT(object):
+class _DEFERRED_ELEMENT_CONSTRAINT:
     pass
 
 
-class _ELEMENT_CONSTRAINT(object):
+class _ELEMENT_CONSTRAINT:
     pass
 
 
-class _DEFERRED_BEFORE(object):
+class _DEFERRED_BEFORE:
     pass
 
 
-class _DEFERRED_AFTER(object):
+class _DEFERRED_AFTER:
     pass
 
 
-class _DEFERRED_AT(object):
+class _DEFERRED_AT:
     pass
 
 
-class _BEFORE(object):
+class _BEFORE:
     pass
 
 
-class _AT(object):
+class _AT:
     pass
 
 
-class _IMPLIES(object):
+class _IMPLIES:
     pass
 
 
-class _LAND(object):
+class _LAND:
     pass
 
 
-class _LOR(object):
+class _LOR:
     pass
 
 
-class _XOR(object):
+class _XOR:
     pass
 
 
-class _EQUIVALENT_TO(object):
+class _EQUIVALENT_TO:
     pass
 
 
@@ -1130,7 +1130,7 @@ def collect_valid_components(model, active=True, sort=None, valid=set(), targets
 @WriterFactory.register(
     'docplex_model', 'Generate the corresponding docplex model object'
 )
-class DocplexWriter(object):
+class DocplexWriter:
     CONFIG = ConfigDict('docplex_model_writer')
     CONFIG.declare(
         'symbolic_solver_labels',
@@ -1247,7 +1247,7 @@ def write(self, model, **options):
 
 
 @SolverFactory.register('cp_optimizer', doc='Direct interface to CPLEX CP Optimizer')
-class CPOptimizerSolver(object):
+class CPOptimizerSolver:
     CONFIG = ConfigDict("cp_optimizer_solver")
     CONFIG.declare(
         'symbolic_solver_labels',
diff --git a/pyomo/contrib/cspline_external/build.py b/pyomo/contrib/cspline_external/build.py
index 4fc573d6710..15c1032f6f4 100644
--- a/pyomo/contrib/cspline_external/build.py
+++ b/pyomo/contrib/cspline_external/build.py
@@ -23,7 +23,7 @@ def build_cspline_external(user_args=[], parallel=None):
     )
 
 
-class ASLCsplineExternalBuilder(object):
+class ASLCsplineExternalBuilder:
     def __call__(self, parallel):
         return build_cspline_external(parallel=parallel)
 
diff --git a/pyomo/contrib/doe/tests/experiment_class_example_flags.py b/pyomo/contrib/doe/tests/experiment_class_example_flags.py
index fc2acb816e5..4fcdff3e482 100644
--- a/pyomo/contrib/doe/tests/experiment_class_example_flags.py
+++ b/pyomo/contrib/doe/tests/experiment_class_example_flags.py
@@ -45,7 +45,7 @@ def expand_model_components(m, base_components, index_sets):
                 yield val[j]
 
 
-class BadExperiment(object):
+class BadExperiment:
     def __init__(self):
         self.model = None
 
diff --git a/pyomo/contrib/fbbt/fbbt.py b/pyomo/contrib/fbbt/fbbt.py
index c1f6fd4ad01..053ed129bf5 100644
--- a/pyomo/contrib/fbbt/fbbt.py
+++ b/pyomo/contrib/fbbt/fbbt.py
@@ -1579,7 +1579,7 @@ def compute_bounds_on_expr(expr, ignore_fixed=False):
     return lb, ub
 
 
-class BoundsManager(object):
+class BoundsManager:
     def __init__(self, comp):
         self._vars = ComponentSet()
         self._saved_bounds = list()
diff --git a/pyomo/contrib/fbbt/interval.py b/pyomo/contrib/fbbt/interval.py
index 3d96dd14f36..f987c92c97a 100644
--- a/pyomo/contrib/fbbt/interval.py
+++ b/pyomo/contrib/fbbt/interval.py
@@ -17,7 +17,7 @@
 inf = float('inf')
 
 
-class _bool_flag(object):
+class _bool_flag:
     def __init__(self, val):
         self._val = val
 
diff --git a/pyomo/contrib/fbbt/tests/test_fbbt.py b/pyomo/contrib/fbbt/tests/test_fbbt.py
index d5a56232537..8c8913fa3e5 100644
--- a/pyomo/contrib/fbbt/tests/test_fbbt.py
+++ b/pyomo/contrib/fbbt/tests/test_fbbt.py
@@ -33,7 +33,7 @@ class DummyExpr(ProductExpression):
     pass
 
 
-class FbbtTestBase(object):
+class FbbtTestBase:
     """
     These tests are set up weird, but it is for a good reason.
     The FBBT code is duplicated in pyomo.contrib.appsi for
diff --git a/pyomo/contrib/fbbt/tests/test_interval.py b/pyomo/contrib/fbbt/tests/test_interval.py
index c27c3a48491..8ab9e88d79b 100644
--- a/pyomo/contrib/fbbt/tests/test_interval.py
+++ b/pyomo/contrib/fbbt/tests/test_interval.py
@@ -23,7 +23,7 @@ def isfinite(x):
         return not (math.isnan(x) or math.isinf(x))
 
 
-class IntervalTestBase(object):
+class IntervalTestBase:
     """
     These tests are set up weird, but it is for a good reason.
     The interval arithmetic code is duplicated in pyomo.contrib.appsi for
diff --git a/pyomo/contrib/gdpopt/GDPopt.py b/pyomo/contrib/gdpopt/GDPopt.py
index dbfdc0ecfc2..96d36447ac4 100644
--- a/pyomo/contrib/gdpopt/GDPopt.py
+++ b/pyomo/contrib/gdpopt/GDPopt.py
@@ -67,7 +67,7 @@ def _handle_strategy_deprecation(config):
     doc='The GDPopt decomposition-based '
     'Generalized Disjunctive Programming (GDP) solver',
 )
-class GDPoptSolver(object):
+class GDPoptSolver:
     """Decomposition solver for Generalized Disjunctive Programming (GDP)
     problems.
 
diff --git a/pyomo/contrib/gdpopt/oa_algorithm_utils.py b/pyomo/contrib/gdpopt/oa_algorithm_utils.py
index d0410dd68b9..d06f48da9af 100644
--- a/pyomo/contrib/gdpopt/oa_algorithm_utils.py
+++ b/pyomo/contrib/gdpopt/oa_algorithm_utils.py
@@ -16,7 +16,7 @@
 from pyomo.opt import TerminationCondition as tc
 
 
-class _OAAlgorithmMixIn(object):
+class _OAAlgorithmMixIn:
     def _fix_discrete_soln_solve_subproblem_and_add_cuts(
         self, discrete_prob_util_block, subprob_util_block, config
     ):
diff --git a/pyomo/contrib/gdpopt/solve_subproblem.py b/pyomo/contrib/gdpopt/solve_subproblem.py
index efb2cf6336c..bd71a07193d 100644
--- a/pyomo/contrib/gdpopt/solve_subproblem.py
+++ b/pyomo/contrib/gdpopt/solve_subproblem.py
@@ -240,7 +240,7 @@ def detect_unfixed_discrete_vars(model):
     return var_set
 
 
-class preprocess_subproblem(object):
+class preprocess_subproblem:
     def __init__(self, util_block, config):
         self.util_block = util_block
         self.config = config
diff --git a/pyomo/contrib/gdpopt/util.py b/pyomo/contrib/gdpopt/util.py
index 43ca8a6e277..5d63ac8affa 100644
--- a/pyomo/contrib/gdpopt/util.py
+++ b/pyomo/contrib/gdpopt/util.py
@@ -37,7 +37,7 @@
 from pyomo.opt import SolverFactory
 
 
-class _DoNothing(object):
+class _DoNothing:
     """Do nothing, literally.
 
     This class is used in situations of "do something if attribute exists."
@@ -56,7 +56,7 @@ def _do_nothing(*args, **kwargs):
         return _do_nothing
 
 
-class SuppressInfeasibleWarning(object):
+class SuppressInfeasibleWarning:
     """Suppress the infeasible model warning message from solve().
 
     The "WARNING: Loading a SolverResults object with a warning status" warning
@@ -217,7 +217,7 @@ def fix_discrete_var(var, val, config):
             var.fix(val, skip_validation=True)
 
 
-class fix_discrete_solution_in_subproblem(object):
+class fix_discrete_solution_in_subproblem:
     def __init__(
         self,
         true_disjuncts,
diff --git a/pyomo/contrib/incidence_analysis/interface.py b/pyomo/contrib/incidence_analysis/interface.py
index 45a783019b7..8467ab69b95 100644
--- a/pyomo/contrib/incidence_analysis/interface.py
+++ b/pyomo/contrib/incidence_analysis/interface.py
@@ -244,7 +244,7 @@ def get_numeric_incidence_matrix(variables, constraints):
     return nlp.extract_submatrix_jacobian(variables, constraints)
 
 
-class IncidenceGraphInterface(object):
+class IncidenceGraphInterface:
     """An interface for applying graph algorithms to Pyomo variables and
     constraints
 
diff --git a/pyomo/contrib/incidence_analysis/tests/test_incidence.py b/pyomo/contrib/incidence_analysis/tests/test_incidence.py
index 1018a77c139..38ad30f2511 100644
--- a/pyomo/contrib/incidence_analysis/tests/test_incidence.py
+++ b/pyomo/contrib/incidence_analysis/tests/test_incidence.py
@@ -38,7 +38,7 @@ def test_uninitialized_value_error_message(self):
             pyo.value(1 + m.x[1] * m.x[2])
 
 
-class _TestIncidence(object):
+class _TestIncidence:
     """Base class with tests for get_incident_variables that should be
     independent of the method used
 
@@ -73,7 +73,7 @@ def test_incidence_with_named_expression(self):
         self.assertEqual(ComponentSet(variables), ComponentSet(m.x[:]))
 
 
-class _TestIncidenceLinearOnly(object):
+class _TestIncidenceLinearOnly:
     """Tests for methods that support linear_only"""
 
     def _get_incident_variables(self, expr):
@@ -99,7 +99,7 @@ def test_linear_only(self):
         self.assertEqual(ComponentSet(variables), ComponentSet([m.x[1], m.x[2]]))
 
 
-class _TestIncidenceLinearCancellation(object):
+class _TestIncidenceLinearCancellation:
     """Tests for methods that perform linear cancellation"""
 
     def _get_incident_variables(self, expr):
diff --git a/pyomo/contrib/interior_point/interior_point.py b/pyomo/contrib/interior_point/interior_point.py
index f67b3c2cd7f..ca901c84c50 100644
--- a/pyomo/contrib/interior_point/interior_point.py
+++ b/pyomo/contrib/interior_point/interior_point.py
@@ -39,7 +39,7 @@ class InteriorPointStatus(enum.Enum):
     error = 1
 
 
-class LinearSolveContext(object):
+class LinearSolveContext:
     def __init__(
         self,
         interior_point_logger,
@@ -76,7 +76,7 @@ def __exit__(self, et, ev, tb):
 #
 #       Define a method for logging IP_reg_info to the linear solver log
 #       Method can be called within linear_solve_context
-class FactorizationContext(object):
+class FactorizationContext:
     def __init__(self, logger):
         # Any reason to pass in a logging level here?
         # ^ So the "regularization log" can have its own outlvl
@@ -126,7 +126,7 @@ def log_info(self, _iter, reg_iter, num_realloc, coef, neg_eig, status):
         )
 
 
-class InteriorPointSolver(object):
+class InteriorPointSolver:
     """
     Class for creating interior point solvers with different options
     """
diff --git a/pyomo/contrib/mcpp/build.py b/pyomo/contrib/mcpp/build.py
index b6975f1a4c1..d0686f29cdb 100644
--- a/pyomo/contrib/mcpp/build.py
+++ b/pyomo/contrib/mcpp/build.py
@@ -102,7 +102,7 @@ def get_ext_filename(self, ext_name):
         shutil.rmtree(tmpdir)
 
 
-class MCPPBuilder(object):
+class MCPPBuilder:
     def __call__(self, parallel):
         return build_mcpp()
 
diff --git a/pyomo/contrib/mcpp/pyomo_mcpp.py b/pyomo/contrib/mcpp/pyomo_mcpp.py
index 5146cb4a0a7..3d0e8de1cfa 100644
--- a/pyomo/contrib/mcpp/pyomo_mcpp.py
+++ b/pyomo/contrib/mcpp/pyomo_mcpp.py
@@ -384,7 +384,7 @@ def finalizeResult(self, node_result):
         return node_result
 
 
-class McCormick(object):
+class McCormick:
     """
     This class takes the constructed expression from MCPP_Visitor and
     allows for MC methods to be performed on pyomo expressions.
diff --git a/pyomo/contrib/mindtpy/MindtPy.py b/pyomo/contrib/mindtpy/MindtPy.py
index 1a8d807ffaf..a79f03d8979 100644
--- a/pyomo/contrib/mindtpy/MindtPy.py
+++ b/pyomo/contrib/mindtpy/MindtPy.py
@@ -70,7 +70,7 @@
 @SolverFactory.register(
     'mindtpy', doc='MindtPy: Mixed-Integer Nonlinear Decomposition Toolbox in Pyomo'
 )
-class MindtPySolver(object):
+class MindtPySolver:
     """
     Decomposition solver for Mixed-Integer Nonlinear Programming (MINLP) problems.
 
diff --git a/pyomo/contrib/mindtpy/algorithm_base_class.py b/pyomo/contrib/mindtpy/algorithm_base_class.py
index 53bed15e018..bdabd263072 100644
--- a/pyomo/contrib/mindtpy/algorithm_base_class.py
+++ b/pyomo/contrib/mindtpy/algorithm_base_class.py
@@ -83,7 +83,7 @@
 )
 
 
-class _MindtPyAlgorithm(object):
+class _MindtPyAlgorithm:
     def __init__(self, **kwds):
         """
         This is a common init method for all the MindtPy algorithms, so that we
diff --git a/pyomo/contrib/mpc/data/dynamic_data_base.py b/pyomo/contrib/mpc/data/dynamic_data_base.py
index 095442fc7d3..4115c74c522 100644
--- a/pyomo/contrib/mpc/data/dynamic_data_base.py
+++ b/pyomo/contrib/mpc/data/dynamic_data_base.py
@@ -38,7 +38,7 @@ def _is_iterable(obj):
                 raise err
 
 
-class _DynamicDataBase(object):
+class _DynamicDataBase:
     """
     A base class for storing data associated with time-indexed variables.
 
diff --git a/pyomo/contrib/mpc/interfaces/model_interface.py b/pyomo/contrib/mpc/interfaces/model_interface.py
index a38a31c7b6f..a4934b7528e 100644
--- a/pyomo/contrib/mpc/interfaces/model_interface.py
+++ b/pyomo/contrib/mpc/interfaces/model_interface.py
@@ -49,7 +49,7 @@ def _to_iterable(item):
         yield item
 
 
-class DynamicModelInterface(object):
+class DynamicModelInterface:
     """A helper class for working with dynamic models, e.g. those where
     many components are indexed by some ordered set referred to as "time."
 
diff --git a/pyomo/contrib/mpc/interfaces/var_linker.py b/pyomo/contrib/mpc/interfaces/var_linker.py
index 1f3731163fd..5da4821f22c 100644
--- a/pyomo/contrib/mpc/interfaces/var_linker.py
+++ b/pyomo/contrib/mpc/interfaces/var_linker.py
@@ -12,7 +12,7 @@
 from pyomo.contrib.mpc.interfaces.copy_values import copy_values_at_time
 
 
-class DynamicVarLinker(object):
+class DynamicVarLinker:
     """
     The purpose of this class is so that we do not have
     to call find_component or construct ComponentUIDs in a loop
diff --git a/pyomo/contrib/multistart/multi.py b/pyomo/contrib/multistart/multi.py
index 8cdc43143f0..5b15f65c92f 100644
--- a/pyomo/contrib/multistart/multi.py
+++ b/pyomo/contrib/multistart/multi.py
@@ -30,7 +30,7 @@
 
 @SolverFactory.register('multistart', doc='MultiStart solver for NLPs')
 @document_kwargs_from_configdict('CONFIG')
-class MultiStart(object):
+class MultiStart:
     """Solver wrapper that initializes at multiple starting points.
 
     # TODO: also return appropriate duals
diff --git a/pyomo/contrib/parmest/parmest.py b/pyomo/contrib/parmest/parmest.py
index ea9dfc00640..4f173811b5a 100644
--- a/pyomo/contrib/parmest/parmest.py
+++ b/pyomo/contrib/parmest/parmest.py
@@ -235,7 +235,7 @@ def SSE(model):
     return expr
 
 
-class Estimator(object):
+class Estimator:
     """
     Parameter estimation class
 
@@ -1425,7 +1425,7 @@ def group_data(data, groupby_column_name, use_mean=None):
     return grouped_data
 
 
-class _DeprecatedSecondStageCostExpr(object):
+class _DeprecatedSecondStageCostExpr:
     """
     Class to pass objective expression into the Pyomo model
     """
@@ -1438,7 +1438,7 @@ def __call__(self, model):
         return self._ssc_function(model, self._data)
 
 
-class _DeprecatedEstimator(object):
+class _DeprecatedEstimator:
     """
     Parameter estimation class
 
diff --git a/pyomo/contrib/parmest/scenariocreator.py b/pyomo/contrib/parmest/scenariocreator.py
index 3be02967a63..82b0b2de588 100644
--- a/pyomo/contrib/parmest/scenariocreator.py
+++ b/pyomo/contrib/parmest/scenariocreator.py
@@ -19,7 +19,7 @@
 logger = logging.getLogger(__name__)
 
 
-class ScenarioSet(object):
+class ScenarioSet:
     """
     Class to hold scenario sets
 
@@ -94,7 +94,7 @@ def write_csv(self, filename):
                 f.write('\n')
 
 
-class ParmestScen(object):
+class ParmestScen:
     """A little container for scenarios; the Args are the attributes.
 
     Args:
@@ -113,7 +113,7 @@ def __init__(self, name, ThetaVals, probability):
 ############################################################
 
 
-class ScenarioCreator(object):
+class ScenarioCreator:
     """Create scenarios from parmest.
 
     Args:
diff --git a/pyomo/contrib/pynumero/algorithms/solvers/cyipopt_solver.py b/pyomo/contrib/pynumero/algorithms/solvers/cyipopt_solver.py
index 9464cfa53f8..d7ed9ff35cd 100644
--- a/pyomo/contrib/pynumero/algorithms/solvers/cyipopt_solver.py
+++ b/pyomo/contrib/pynumero/algorithms/solvers/cyipopt_solver.py
@@ -180,7 +180,7 @@
 }
 
 
-class CyIpoptSolver(object):
+class CyIpoptSolver:
     def __init__(self, problem_interface, options=None):
         """Create an instance of the CyIpoptSolver. You must
         provide a problem_interface that corresponds to
@@ -243,7 +243,7 @@ def _numpy_vector(val):
     return ans
 
 
-class PyomoCyIpoptSolver(object):
+class PyomoCyIpoptSolver:
     CONFIG = ConfigBlock("cyipopt")
     CONFIG.declare(
         "tee",
diff --git a/pyomo/contrib/pynumero/algorithms/solvers/implicit_functions.py b/pyomo/contrib/pynumero/algorithms/solvers/implicit_functions.py
index a0c69507a0b..d16b738b8fc 100644
--- a/pyomo/contrib/pynumero/algorithms/solvers/implicit_functions.py
+++ b/pyomo/contrib/pynumero/algorithms/solvers/implicit_functions.py
@@ -38,7 +38,7 @@
 )
 
 
-class NlpSolverBase(object):
+class NlpSolverBase:
     """A base class that solves an NLP object
 
     Subclasses should implement this interface for compatibility with
@@ -118,7 +118,7 @@ def solve(self, x0=None):
         return res
 
 
-class PyomoImplicitFunctionBase(object):
+class PyomoImplicitFunctionBase:
     """A base class defining an API for implicit functions defined using
     Pyomo components. In particular, this is the API required by
     ExternalPyomoModel.
diff --git a/pyomo/contrib/pynumero/algorithms/solvers/scipy_solvers.py b/pyomo/contrib/pynumero/algorithms/solvers/scipy_solvers.py
index a4c28392c24..ba3fb6e30cf 100644
--- a/pyomo/contrib/pynumero/algorithms/solvers/scipy_solvers.py
+++ b/pyomo/contrib/pynumero/algorithms/solvers/scipy_solvers.py
@@ -255,7 +255,7 @@ def solve(self, x0=None):
         return results
 
 
-class PyomoScipySolver(object):
+class PyomoScipySolver:
     def __init__(self, options=None):
         if options is None:
             options = {}
diff --git a/pyomo/contrib/pynumero/algorithms/solvers/square_solver_base.py b/pyomo/contrib/pynumero/algorithms/solvers/square_solver_base.py
index 43f48211d3d..e4b9de6387b 100644
--- a/pyomo/contrib/pynumero/algorithms/solvers/square_solver_base.py
+++ b/pyomo/contrib/pynumero/algorithms/solvers/square_solver_base.py
@@ -15,7 +15,7 @@
 from pyomo.util.subsystems import create_subsystem_block
 
 
-class SquareNlpSolverBase(object):
+class SquareNlpSolverBase:
     """A base class for NLP solvers that act on a square system
     of equality constraints.
 
diff --git a/pyomo/contrib/pynumero/algorithms/solvers/tests/test_implicit_functions.py b/pyomo/contrib/pynumero/algorithms/solvers/tests/test_implicit_functions.py
index b2e9b9eace7..d2893a7f9f8 100644
--- a/pyomo/contrib/pynumero/algorithms/solvers/tests/test_implicit_functions.py
+++ b/pyomo/contrib/pynumero/algorithms/solvers/tests/test_implicit_functions.py
@@ -42,7 +42,7 @@
     )
 
 
-class ImplicitFunction1(object):
+class ImplicitFunction1:
     def __init__(self):
         self._model = self._make_model()
 
@@ -137,7 +137,7 @@ def _make_model(self):
         return m
 
 
-class ImplicitFunctionInputsDontAppear(object):
+class ImplicitFunctionInputsDontAppear:
     """This is an implicit function designed to test the edge case
     where inputs do not appear in the system defining the implicit
     function (i.e. the function is constant).
diff --git a/pyomo/contrib/pynumero/asl.py b/pyomo/contrib/pynumero/asl.py
index cffaaeecc35..e28b8d60240 100644
--- a/pyomo/contrib/pynumero/asl.py
+++ b/pyomo/contrib/pynumero/asl.py
@@ -239,7 +239,7 @@ def _LoadASLInterface(libname):
     return ASLib, interface_version
 
 
-class AmplInterface(object):
+class AmplInterface:
     libname = _NotSet
     ASLib = None
     interface_version = None
diff --git a/pyomo/contrib/pynumero/build.py b/pyomo/contrib/pynumero/build.py
index 015c7246850..94bb9fea148 100644
--- a/pyomo/contrib/pynumero/build.py
+++ b/pyomo/contrib/pynumero/build.py
@@ -23,7 +23,7 @@ def build_pynumero(user_args=[], parallel=None):
     )
 
 
-class PyNumeroBuilder(object):
+class PyNumeroBuilder:
     def __call__(self, parallel):
         return build_pynumero(parallel=parallel)
 
diff --git a/pyomo/contrib/pynumero/examples/callback/cyipopt_functor_callback.py b/pyomo/contrib/pynumero/examples/callback/cyipopt_functor_callback.py
index 98d2e786b2d..24781b6ef68 100644
--- a/pyomo/contrib/pynumero/examples/callback/cyipopt_functor_callback.py
+++ b/pyomo/contrib/pynumero/examples/callback/cyipopt_functor_callback.py
@@ -19,7 +19,7 @@
 """
 
 
-class ResidualsTableCallback(object):
+class ResidualsTableCallback:
     def __init__(self):
         self._residuals = None
 
diff --git a/pyomo/contrib/pynumero/interfaces/external_grey_box.py b/pyomo/contrib/pynumero/interfaces/external_grey_box.py
index c4ed59ee19f..ec0c1b35b29 100644
--- a/pyomo/contrib/pynumero/interfaces/external_grey_box.py
+++ b/pyomo/contrib/pynumero/interfaces/external_grey_box.py
@@ -89,7 +89,7 @@
 """
 
 
-class ExternalGreyBoxModel(object):
+class ExternalGreyBoxModel:
     """
     This is the base class for building external input output models
     for use with Pyomo and CyIpopt. See the module documentation above,
diff --git a/pyomo/contrib/pynumero/interfaces/pyomo_nlp.py b/pyomo/contrib/pynumero/interfaces/pyomo_nlp.py
index 78e8ca5faa5..62696e3b9c9 100644
--- a/pyomo/contrib/pynumero/interfaces/pyomo_nlp.py
+++ b/pyomo/contrib/pynumero/interfaces/pyomo_nlp.py
@@ -1185,7 +1185,7 @@ def load_state_into_pyomo(self, bound_multipliers=None):
                 )
 
 
-class _ExternalGreyBoxModelHelper(object):
+class _ExternalGreyBoxModelHelper:
     def __init__(self, ex_grey_box_block, vardata_to_idx, con_offset):
         """This helper takes an ExternalGreyBoxModel and provides the residual,
         Jacobian, and Hessian computation mapped to the correct variable space.
diff --git a/pyomo/contrib/pynumero/interfaces/tests/test_external_pyomo_model.py b/pyomo/contrib/pynumero/interfaces/tests/test_external_pyomo_model.py
index f446951c643..213fdae2914 100644
--- a/pyomo/contrib/pynumero/interfaces/tests/test_external_pyomo_model.py
+++ b/pyomo/contrib/pynumero/interfaces/tests/test_external_pyomo_model.py
@@ -47,7 +47,7 @@
     raise unittest.SkipTest("Need IPOPT to run ExternalPyomoModel tests")
 
 
-class SimpleModel1(object):
+class SimpleModel1:
     def make_model(self):
         m = pyo.ConcreteModel()
         m.x = pyo.Var(initialize=2.0)
@@ -80,7 +80,7 @@ def evaluate_hessian(self, x):
         return 2 + 0.24 / x**4
 
 
-class SimpleModel2(object):
+class SimpleModel2:
     """
     The purpose of this model is to exercise each term in the computation
     of the d2ydx2 Hessian.
@@ -113,7 +113,7 @@ def evaluate_hessian(self, x):
         return 2 + 6 * 0.2 ** (2 / 3) / x**4
 
 
-class SimpleModel2by2_1(object):
+class SimpleModel2by2_1:
     """
     The purpose of this model is to test second derivative computation
     when the external model is nonlinear only in x. This exercises
@@ -228,7 +228,7 @@ def evaluate_external_hessian(self, x):
         return [dy0dxdx, dy1dxdx]
 
 
-class Model2by2(object):
+class Model2by2:
     """
     The purpose of this model is to test d2ydx2 Hessian computation when
     transposes result in a nontrivial modification of Hessian/Jacobian
diff --git a/pyomo/contrib/pynumero/interfaces/utils.py b/pyomo/contrib/pynumero/interfaces/utils.py
index 01f495eba09..1cfd36d0725 100644
--- a/pyomo/contrib/pynumero/interfaces/utils.py
+++ b/pyomo/contrib/pynumero/interfaces/utils.py
@@ -143,7 +143,7 @@ def make_lower_triangular_full(lower_triangular_matrix):
     return coo_matrix((data, (row, col)), shape=lower_triangular_matrix.shape)
 
 
-class CondensedSparseSummation(object):
+class CondensedSparseSummation:
     def __init__(self, list_of_matrices):
         """
         This class is used to perform a summation of sparse matrices
diff --git a/pyomo/contrib/pynumero/linalg/base.py b/pyomo/contrib/pynumero/linalg/base.py
index 748a8b86114..210c549a126 100644
--- a/pyomo/contrib/pynumero/linalg/base.py
+++ b/pyomo/contrib/pynumero/linalg/base.py
@@ -27,7 +27,7 @@ class LinearSolverStatus(enum.Enum):
     max_iter = 5
 
 
-class LinearSolverResults(object):
+class LinearSolverResults:
     def __init__(self, status: Optional[LinearSolverStatus] = None):
         self.status = status
 
diff --git a/pyomo/contrib/pynumero/linalg/ma27.py b/pyomo/contrib/pynumero/linalg/ma27.py
index 7d8cfc00fe3..c2a7cbbd4a3 100644
--- a/pyomo/contrib/pynumero/linalg/ma27.py
+++ b/pyomo/contrib/pynumero/linalg/ma27.py
@@ -16,7 +16,7 @@
 import os
 
 
-class MA27Interface(object):
+class MA27Interface:
     libname = _NotSet
 
     @classmethod
diff --git a/pyomo/contrib/pynumero/linalg/ma57.py b/pyomo/contrib/pynumero/linalg/ma57.py
index 6f07a8fea90..bd1a0004ef2 100644
--- a/pyomo/contrib/pynumero/linalg/ma57.py
+++ b/pyomo/contrib/pynumero/linalg/ma57.py
@@ -17,7 +17,7 @@
 import os
 
 
-class MA57Interface(object):
+class MA57Interface:
     libname = _NotSet
 
     @classmethod
diff --git a/pyomo/contrib/pynumero/sparse/base_block.py b/pyomo/contrib/pynumero/sparse/base_block.py
index 293ca34c6f0..42f0ec16549 100644
--- a/pyomo/contrib/pynumero/sparse/base_block.py
+++ b/pyomo/contrib/pynumero/sparse/base_block.py
@@ -14,7 +14,7 @@
 from ..dependencies import numpy as np
 
 
-class BaseBlockVector(object):
+class BaseBlockVector:
     """Base class for block vectors"""
 
     def __init__(self):
@@ -132,7 +132,7 @@ def tobytes(self, order='C'):
         raise NotImplementedError(msg)
 
 
-class BaseBlockMatrix(object):
+class BaseBlockMatrix:
     """Base class for block matrices"""
 
     def __init__(self):
diff --git a/pyomo/contrib/pyros/config.py b/pyomo/contrib/pyros/config.py
index fde4f35375b..f5d1b0da2d0 100644
--- a/pyomo/contrib/pyros/config.py
+++ b/pyomo/contrib/pyros/config.py
@@ -154,7 +154,7 @@ def uncertain_param_data_validator(uncertain_obj):
             )
 
 
-class InputDataStandardizer(object):
+class InputDataStandardizer:
     """
     Domain validator for an object that is castable to
     a list of Pyomo component data objects.
@@ -246,7 +246,7 @@ class SolverNotResolvable(PyomoException):
     """
 
 
-class SolverResolvable(object):
+class SolverResolvable:
     """
     Callable for casting an object (such as a str)
     to a Pyomo solver.
@@ -369,7 +369,7 @@ def domain_name(self):
         return "str or Solver"
 
 
-class SolverIterable(object):
+class SolverIterable:
     """
     Callable for casting an iterable (such as a list of strs)
     to a list of Pyomo solvers.
diff --git a/pyomo/contrib/pyros/pyros.py b/pyomo/contrib/pyros/pyros.py
index 4da7b6672cd..58d34edaf18 100644
--- a/pyomo/contrib/pyros/pyros.py
+++ b/pyomo/contrib/pyros/pyros.py
@@ -81,7 +81,7 @@ def _get_pyomo_version_info():
     doc="Robust optimization (RO) solver implementing "
     "the generalized robust cutting-set algorithm (GRCS)",
 )
-class PyROS(object):
+class PyROS:
     '''
     PyROS (Pyomo Robust Optimization Solver) implementing a
     generalized robust cutting-set algorithm (GRCS)
diff --git a/pyomo/contrib/pyros/solve_data.py b/pyomo/contrib/pyros/solve_data.py
index 03f9a9b1de3..f959ee737d6 100644
--- a/pyomo/contrib/pyros/solve_data.py
+++ b/pyomo/contrib/pyros/solve_data.py
@@ -14,7 +14,7 @@
 """
 
 
-class ROSolveResults(object):
+class ROSolveResults:
     """
     PyROS solver results object.
 
diff --git a/pyomo/contrib/pyros/tests/test_grcs.py b/pyomo/contrib/pyros/tests/test_grcs.py
index 74cc7ad3039..d42b1c28a41 100644
--- a/pyomo/contrib/pyros/tests/test_grcs.py
+++ b/pyomo/contrib/pyros/tests/test_grcs.py
@@ -113,7 +113,7 @@
 
 
 # @SolverFactory.register("time_delay_solver")
-class TimeDelaySolver(object):
+class TimeDelaySolver:
     """
     Solver which puts program to sleep for a specified
     duration after having been invoked a specified number
@@ -4227,7 +4227,7 @@ def test_validate_pyros_inputs_user_var_partitioning_obj_only(self):
 
 
 # @SolverFactory.register("subsolver_error__solver")
-class SubsolverErrorSolver(object):
+class SubsolverErrorSolver:
     """
     Solver that returns a bad termination condition
     to purposefully create an SP subsolver error.
diff --git a/pyomo/contrib/satsolver/satsolver.py b/pyomo/contrib/satsolver/satsolver.py
index 07e5199f401..e8fe2d85b97 100644
--- a/pyomo/contrib/satsolver/satsolver.py
+++ b/pyomo/contrib/satsolver/satsolver.py
@@ -51,7 +51,7 @@ def satisfiable(model, logger=None):
         raise ValueError('Unknown result: %s' % result)
 
 
-class SMTSatSolver(object):
+class SMTSatSolver:
     """
     Satisfiability solver that checks constraint feasibility through use of
     z3 Sat Solver. Object stores expressions and variables in form consistent
diff --git a/pyomo/contrib/sensitivity_toolbox/k_aug.py b/pyomo/contrib/sensitivity_toolbox/k_aug.py
index 6231514254d..b0bf357038c 100644
--- a/pyomo/contrib/sensitivity_toolbox/k_aug.py
+++ b/pyomo/contrib/sensitivity_toolbox/k_aug.py
@@ -42,7 +42,7 @@
 ]
 
 
-class InTempDir(object):
+class InTempDir:
     def __init__(self, suffix=None, prefix=None, dir=None):
         self._suffix = suffix
         self._prefix = prefix
@@ -63,7 +63,7 @@ def __exit__(self, ex_type, ex_val, ex_bt):
         TempfileManager.pop()
 
 
-class K_augInterface(object):
+class K_augInterface:
     """
     k_aug and dot_sens store information in the user's filesystem,
     some of which is mandatory for subsequent calls.
diff --git a/pyomo/contrib/sensitivity_toolbox/sens.py b/pyomo/contrib/sensitivity_toolbox/sens.py
index 22ed7486311..133c9c0b614 100644
--- a/pyomo/contrib/sensitivity_toolbox/sens.py
+++ b/pyomo/contrib/sensitivity_toolbox/sens.py
@@ -133,7 +133,7 @@ def _add_sensitivity_suffixes(block):
             block.add_component(name, Suffix(direction=direction))
 
 
-class _NotAnIndex(object):
+class _NotAnIndex:
     pass
 
 
@@ -509,7 +509,7 @@ def line_num(file_name, target):
     raise Exception(file_name + " does not include " + target)
 
 
-class SensitivityInterface(object):
+class SensitivityInterface:
     def __init__(self, instance, clone_model=True):
         """Constructor clones model if necessary and attaches
         to this object.
diff --git a/pyomo/contrib/simplification/build.py b/pyomo/contrib/simplification/build.py
index 038bba32904..40ddc81a67d 100644
--- a/pyomo/contrib/simplification/build.py
+++ b/pyomo/contrib/simplification/build.py
@@ -176,7 +176,7 @@ def run(self):
     dist.run_command('build_ext')
 
 
-class GiNaCInterfaceBuilder(object):
+class GiNaCInterfaceBuilder:
     def __call__(self, parallel):
         return build_ginac_interface(parallel)
 
diff --git a/pyomo/contrib/simplification/simplify.py b/pyomo/contrib/simplification/simplify.py
index c59e25138dd..0c184d04cca 100644
--- a/pyomo/contrib/simplification/simplify.py
+++ b/pyomo/contrib/simplification/simplify.py
@@ -40,7 +40,7 @@ def simplify_with_ginac(expr: NumericExpression, ginac_interface):
     return ginac_interface.from_ginac(ginac_expr.normal())
 
 
-class Simplifier(object):
+class Simplifier:
     class Mode(NamedIntEnum):
         auto = 0
         sympy = 1
diff --git a/pyomo/contrib/trustregion/TRF.py b/pyomo/contrib/trustregion/TRF.py
index 53d440845b9..7a444730774 100644
--- a/pyomo/contrib/trustregion/TRF.py
+++ b/pyomo/contrib/trustregion/TRF.py
@@ -428,7 +428,7 @@ def _trf_config():
     'trustregion',
     doc='Trust region algorithm "solver" for black box/glass box optimization',
 )
-class TrustRegionSolver(object):
+class TrustRegionSolver:
     """
     The Trust Region Solver is a 'solver' based on the 2016/2018/2020 AiChE
     papers by Eason (2016/2018), Yoshio (2020), and Biegler.
diff --git a/pyomo/contrib/trustregion/interface.py b/pyomo/contrib/trustregion/interface.py
index 6f8d74fb997..b075fa85577 100644
--- a/pyomo/contrib/trustregion/interface.py
+++ b/pyomo/contrib/trustregion/interface.py
@@ -95,7 +95,7 @@ def exitNode(self, node, data):
         return _output
 
 
-class TRFInterface(object):
+class TRFInterface:
     """
     Pyomo interface for Trust Region algorithm.
     """
diff --git a/pyomo/contrib/viewer/model_browser.py b/pyomo/contrib/viewer/model_browser.py
index 17ae37c1443..2365ae86fe7 100644
--- a/pyomo/contrib/viewer/model_browser.py
+++ b/pyomo/contrib/viewer/model_browser.py
@@ -50,11 +50,11 @@
 
 # This lets the file be imported when the Qt UI is not available (or
 # when building docs), but you won't be able to use it
-class _ModelBrowserUI(object):
+class _ModelBrowserUI:
     pass
 
 
-class _ModelBrowser(object):
+class _ModelBrowser:
     pass
 
 
@@ -179,7 +179,7 @@ def update_model(self):
         self.datmodel.update_model()
 
 
-class ComponentDataItem(object):
+class ComponentDataItem:
     """
     This is a container for a Pyomo component to be displayed in a model tree
     view.
diff --git a/pyomo/contrib/viewer/model_select.py b/pyomo/contrib/viewer/model_select.py
index 39199aa8896..d05e4e4286f 100644
--- a/pyomo/contrib/viewer/model_select.py
+++ b/pyomo/contrib/viewer/model_select.py
@@ -39,11 +39,11 @@
 
 # This lets the file be imported when the Qt UI is not available (or
 # when building docs), but you won't be able to use it
-class _ModelSelectUI(object):
+class _ModelSelectUI:
     pass
 
 
-class _ModelSelect(object):
+class _ModelSelect:
     pass
 
 
diff --git a/pyomo/contrib/viewer/qt.py b/pyomo/contrib/viewer/qt.py
index 0456d0299dd..bb5a6d8cc2c 100644
--- a/pyomo/contrib/viewer/qt.py
+++ b/pyomo/contrib/viewer/qt.py
@@ -53,24 +53,24 @@
 if not available:
     # If Qt is not available, we still want to be able to test as much
     # as we can, so add some dummy classes that allow for testing
-    class Qt(object):
+    class Qt:
         class ItemDataRole(enum.Enum):
             EditRole = 1
             DisplayRole = 2
             ToolTipRole = 3
             ForegroundRole = 4
 
-    class QtCore(object):
+    class QtCore:
         """
         A dummy QtCore class to allow some testing without PyQt
         """
 
-        class QModelIndex(object):
+        class QModelIndex:
             pass
 
         Qt = Qt
 
-    class QAbstractItemModel(object):
+    class QAbstractItemModel:
         """
         A dummy QAbstractItemModel class to allow some testing without PyQt
         """
@@ -78,7 +78,7 @@ class QAbstractItemModel(object):
         def __init__(*args, **kwargs):
             pass
 
-    class QAbstractTableModel(object):
+    class QAbstractTableModel:
         """
         A dummy QAbstractTableModel class to allow some testing without PyQt
         """
@@ -86,14 +86,14 @@ class QAbstractTableModel(object):
         def __init__(*args, **kwargs):
             pass
 
-    class QItemEditorCreatorBase(object):
+    class QItemEditorCreatorBase:
         """
         A dummy QItemEditorCreatorBase class to allow some testing without PyQt
         """
 
         pass
 
-    class QItemDelegate(object):
+    class QItemDelegate:
         """
         A dummy QItemDelegate class to allow some testing without PyQt
         """
@@ -135,8 +135,8 @@ class QItemDelegate(object):
     # if we are building the API documentation.
     if building_documentation():
 
-        class QAbstractItemModel(object):
+        class QAbstractItemModel:
             pass
 
-        class QAbstractTableModel(object):
+        class QAbstractTableModel:
             pass
diff --git a/pyomo/contrib/viewer/residual_table.py b/pyomo/contrib/viewer/residual_table.py
index 51da9f8a861..11fed841b82 100644
--- a/pyomo/contrib/viewer/residual_table.py
+++ b/pyomo/contrib/viewer/residual_table.py
@@ -40,11 +40,11 @@
 
 # This lets the file be imported when the Qt UI is not available (or
 # when building docs), but you won't be able to use it
-class _ResidualTableUI(object):
+class _ResidualTableUI:
     pass
 
 
-class _ResidualTable(object):
+class _ResidualTable:
     pass
 
 
diff --git a/pyomo/contrib/viewer/tests/test_data_model_tree.py b/pyomo/contrib/viewer/tests/test_data_model_tree.py
index b9fd9b8867f..67fbd688b16 100644
--- a/pyomo/contrib/viewer/tests/test_data_model_tree.py
+++ b/pyomo/contrib/viewer/tests/test_data_model_tree.py
@@ -51,7 +51,7 @@
     import pyomo.contrib.viewer.ui as ui
 else:
 
-    class UIData(object):
+    class UIData:
         model = None
 
         def __init__(*args, **kwargs):
diff --git a/pyomo/contrib/viewer/ui.py b/pyomo/contrib/viewer/ui.py
index a3eb06d1c29..7cf96848f80 100644
--- a/pyomo/contrib/viewer/ui.py
+++ b/pyomo/contrib/viewer/ui.py
@@ -53,11 +53,11 @@ def get_ipython():
 # This lets the file be imported when the Qt UI is not available (or
 # when building docs), but you won't be able to use it.  Allowing this
 # will let some basic tests run (and pass) without PyQt
-class _MainWindowUI(object):
+class _MainWindowUI:
     pass
 
 
-class _MainWindow(object):
+class _MainWindow:
     pass
 
 
diff --git a/pyomo/contrib/viewer/ui_data.py b/pyomo/contrib/viewer/ui_data.py
index eecda25f037..0008c21bae6 100644
--- a/pyomo/contrib/viewer/ui_data.py
+++ b/pyomo/contrib/viewer/ui_data.py
@@ -33,7 +33,7 @@
 _log = logging.getLogger(__name__)
 
 
-class UIDataNoUi(object):
+class UIDataNoUi:
     """
     This is the UIData object minus the signals.  This is the base class for
     UIData.  The class is split this way for testing when PyQt is not available.
diff --git a/pyomo/core/base/PyomoModel.py b/pyomo/core/base/PyomoModel.py
index ac11ccdbdcb..c2da52eed5f 100644
--- a/pyomo/core/base/PyomoModel.py
+++ b/pyomo/core/base/PyomoModel.py
@@ -88,7 +88,7 @@ def __init__(self, *args, **kw):
             d[item[-1]] = PyomoConfig._option[item]
 
 
-class ModelSolution(object):
+class ModelSolution:
     def __init__(self):
         self._metadata = {}
         self._metadata['status'] = None
@@ -147,7 +147,7 @@ def __setstate__(self, state):
                 tmp[id(obj)] = (obj, entry)
 
 
-class ModelSolutions(object):
+class ModelSolutions:
     def __init__(self, instance):
         self._instance = weakref_ref(instance)
         self.clear()
diff --git a/pyomo/core/base/block.py b/pyomo/core/base/block.py
index a2d98c9d7e8..27e4ce0f6f0 100644
--- a/pyomo/core/base/block.py
+++ b/pyomo/core/base/block.py
@@ -56,7 +56,7 @@
 logger = logging.getLogger('pyomo.core')
 
 
-class _generic_component_decorator(object):
+class _generic_component_decorator:
     """A generic decorator that wraps Block.__setattr__()
 
     Arguments
@@ -83,7 +83,7 @@ def __call__(self, rule):
         return rule
 
 
-class _component_decorator(object):
+class _component_decorator:
     """A class that wraps the _generic_component_decorator, which remembers
     and provides the Block and component type to the decorator.
 
@@ -102,7 +102,7 @@ def __call__(self, *args, **kwds):
         return _generic_component_decorator(self._component, self._block, *args, **kwds)
 
 
-class SubclassOf(object):
+class SubclassOf:
     """This mocks up a tuple-like interface based on subclass relationship.
 
     Instances of this class present a somewhat tuple-like interface for
@@ -133,7 +133,7 @@ def __iter__(self):
         return iter((self,))
 
 
-class _DeduplicateInfo(object):
+class _DeduplicateInfo:
     """Class implementing a unique component data object filter
 
     This class implements :py:meth:`unique()`, which is an efficient
@@ -243,7 +243,7 @@ def _isNotNone(val):
     return val is not None
 
 
-class _BlockConstruction(object):
+class _BlockConstruction:
     """
     This class holds a "global" dict used when constructing
     (hierarchical) models.
@@ -2401,7 +2401,7 @@ def components_data(block, ctype, sort=None, sort_by_keys=False, sort_by_names=F
 BlockData._Block_reserved_words = set(dir(Block()))
 
 
-class ScalarCustomBlockMixin(object):
+class ScalarCustomBlockMixin:
     def __init__(self, *args, **kwargs):
         # __bases__ for the ScalarCustomBlock is
         #
diff --git a/pyomo/core/base/boolean_var.py b/pyomo/core/base/boolean_var.py
index 915ff82c0ba..46536596832 100644
--- a/pyomo/core/base/boolean_var.py
+++ b/pyomo/core/base/boolean_var.py
@@ -35,7 +35,7 @@
 _logical_var_types = {bool, type(None)}
 
 
-class _DeprecatedImplicitAssociatedBinaryVariable(object):
+class _DeprecatedImplicitAssociatedBinaryVariable:
     __slots__ = ('_boolvar',)
 
     def __init__(self, boolvar):
diff --git a/pyomo/core/base/componentuid.py b/pyomo/core/base/componentuid.py
index 6be935d8fee..ba33647506f 100644
--- a/pyomo/core/base/componentuid.py
+++ b/pyomo/core/base/componentuid.py
@@ -27,7 +27,7 @@
 from pyomo.core.base.reference import Reference
 
 
-class _NotSpecified(object):
+class _NotSpecified:
     pass
 
 
@@ -49,7 +49,7 @@ def _context_err(_type):
     )
 
 
-class ComponentUID(object):
+class ComponentUID:
     """
     A Component unique identifier
 
diff --git a/pyomo/core/base/config.py b/pyomo/core/base/config.py
index ff2cbd7d225..68762c41e5f 100644
--- a/pyomo/core/base/config.py
+++ b/pyomo/core/base/config.py
@@ -20,7 +20,7 @@
 logger = logging.getLogger('pyomo.core')
 
 
-class _PyomoOptions(object):
+class _PyomoOptions:
     def __init__(self):
         self._options_stack = [default_pyomo_config()]
 
diff --git a/pyomo/core/base/constraint.py b/pyomo/core/base/constraint.py
index d9338ab1f70..96f0afec365 100644
--- a/pyomo/core/base/constraint.py
+++ b/pyomo/core/base/constraint.py
@@ -959,7 +959,7 @@ class ConstraintList(IndexedConstraint):
     added an index value is not specified.
     """
 
-    class End(object):
+    class End:
         pass
 
     def __init__(self, **kwargs):
diff --git a/pyomo/core/base/indexed_component.py b/pyomo/core/base/indexed_component.py
index f740dd588c1..8bbcb6fdf55 100644
--- a/pyomo/core/base/indexed_component.py
+++ b/pyomo/core/base/indexed_component.py
@@ -100,11 +100,11 @@ def normalize_index(x):
 normalize_index.flatten = True
 
 
-class _NotFound(object):
+class _NotFound:
     pass
 
 
-class _NotSpecified(object):
+class _NotSpecified:
     pass
 
 
@@ -289,7 +289,7 @@ class IndexedComponent(Component):
 
     """
 
-    class Skip(object):
+    class Skip:
         pass
 
     #
@@ -1188,7 +1188,7 @@ def deactivate(self):
 # Ideally, this would inherit from np.lib.mixins.NDArrayOperatorsMixin,
 # but doing so overrides things like __contains__ in addition to the
 # operators that we are interested in.
-class IndexedComponent_NDArrayMixin(object):
+class IndexedComponent_NDArrayMixin:
     """Support using IndexedComponent with numpy.ndarray
 
     This IndexedComponent mixin class adds support for implicitly using
diff --git a/pyomo/core/base/indexed_component_slice.py b/pyomo/core/base/indexed_component_slice.py
index c0aa0049b47..56833e77002 100644
--- a/pyomo/core/base/indexed_component_slice.py
+++ b/pyomo/core/base/indexed_component_slice.py
@@ -19,7 +19,7 @@
 from pyomo.core.base.global_set import UnindexedComponent_index
 
 
-class IndexedComponent_slice(object):
+class IndexedComponent_slice:
     """Special class for slicing through hierarchical component trees
 
     The basic concept is to interrupt the normal slice generation
@@ -382,7 +382,7 @@ def _freeze(info):
         return info
 
 
-class _slice_generator(object):
+class _slice_generator:
     """Utility (iterator) for generating the elements of one slice
 
     Iterate through the component index and yield the component data
@@ -521,11 +521,11 @@ def _advance_iter_check_complete():
 
 
 # A dummy class that we can use as a named entity below
-class _NotIterable(object):
+class _NotIterable:
     pass
 
 
-class _IndexedComponent_slice_iter(object):
+class _IndexedComponent_slice_iter:
     def __init__(
         self,
         component_slice,
diff --git a/pyomo/core/base/initializer.py b/pyomo/core/base/initializer.py
index 6dd9890c933..ca41bdbdc3f 100644
--- a/pyomo/core/base/initializer.py
+++ b/pyomo/core/base/initializer.py
@@ -363,7 +363,7 @@ def __call__(self, parent, idx, *args):
             return self._fcn(parent, *args, idx)
 
 
-class CountedCallGenerator(object):
+class CountedCallGenerator:
     """Generator implementing the "counted call" initialization scheme
 
     This generator implements the older "counted call" scheme, where the
diff --git a/pyomo/core/base/label.py b/pyomo/core/base/label.py
index 3b53cdb859f..5ebcb19f1de 100644
--- a/pyomo/core/base/label.py
+++ b/pyomo/core/base/label.py
@@ -23,7 +23,7 @@
 # they should be handled in the corresponding solver plugin.
 
 
-class _CharMapper(object):
+class _CharMapper:
     def __init__(self, preserve, translate, other):
         """
         Arguments::
@@ -89,12 +89,12 @@ def alphanum_label_from_name(name):
     return str.translate(name, _alphanum_translation_table)
 
 
-class CuidLabeler(object):
+class CuidLabeler:
     def __call__(self, obj=None):
         return ComponentUID(obj)
 
 
-class CounterLabeler(object):
+class CounterLabeler:
     def __init__(self, start=0):
         self._id = start
 
@@ -103,7 +103,7 @@ def __call__(self, obj=None):
         return self._id
 
 
-class NumericLabeler(object):
+class NumericLabeler:
     def __init__(self, prefix, start=0):
         self.id = start
         self.prefix = prefix
@@ -132,12 +132,12 @@ def remove_obj(self, obj):
 # (particularly PySP), and I don't know how much depends on the labels
 # actually being LP-compliant.
 #
-class CNameLabeler(object):
+class CNameLabeler:
     def __call__(self, obj):
         return obj.getname(True)
 
 
-class LPFileLabeler(object):
+class LPFileLabeler:
     def __call__(self, obj):
         return cpxlp_label_from_name(obj.getname(True))
 
@@ -154,17 +154,17 @@ def remove_obj(self, obj):
 TextLabeler = LPFileLabeler
 
 
-class AlphaNumericTextLabeler(object):
+class AlphaNumericTextLabeler:
     def __call__(self, obj):
         return alphanum_label_from_name(obj.getname(True))
 
 
-class NameLabeler(object):
+class NameLabeler:
     def __call__(self, obj):
         return obj.getname(True)
 
 
-class ShortNameLabeler(object):
+class ShortNameLabeler:
     def __init__(
         self,
         limit,
diff --git a/pyomo/core/base/logical_constraint.py b/pyomo/core/base/logical_constraint.py
index 62300d61740..3670bfb59f6 100644
--- a/pyomo/core/base/logical_constraint.py
+++ b/pyomo/core/base/logical_constraint.py
@@ -434,7 +434,7 @@ class LogicalConstraintList(IndexedLogicalConstraint):
     added an index value is not specified.
     """
 
-    class End(object):
+    class End:
         pass
 
     def __init__(self, **kwargs):
diff --git a/pyomo/core/base/objective.py b/pyomo/core/base/objective.py
index f22a4788bba..feaadd31fbb 100644
--- a/pyomo/core/base/objective.py
+++ b/pyomo/core/base/objective.py
@@ -561,7 +561,7 @@ class ObjectiveList(IndexedObjective):
     an index value is not specified.
     """
 
-    class End(object):
+    class End:
         pass
 
     def __init__(self, **kwargs):
diff --git a/pyomo/core/base/param.py b/pyomo/core/base/param.py
index 7944fadc430..2ede91e5bf9 100644
--- a/pyomo/core/base/param.py
+++ b/pyomo/core/base/param.py
@@ -299,7 +299,7 @@ class Param(IndexedComponent, IndexedComponent_NDArrayMixin):
     DefaultMutable = False
     _ComponentDataClass = ParamData
 
-    class NoValue(object):
+    class NoValue:
         """A dummy type that is pickle-safe that we can use as the default
         value for Params to indicate that no valid value is present."""
 
diff --git a/pyomo/core/base/piecewise.py b/pyomo/core/base/piecewise.py
index 8654b153f87..0190ee7619b 100644
--- a/pyomo/core/base/piecewise.py
+++ b/pyomo/core/base/piecewise.py
@@ -277,7 +277,7 @@ class _PiecewiseData(metaclass=RenamedClass):
     __renamed__version__ = '6.7.2'
 
 
-class _SimpleSinglePiecewise(object):
+class _SimpleSinglePiecewise:
     """
     Called when the piecewise points list has only two points
     """
@@ -321,7 +321,7 @@ def construct(self, pblock, x_var, y_var):
             )
 
 
-class _SimplifiedPiecewise(object):
+class _SimplifiedPiecewise:
     """
     Called when piecewise constraints are simplified due to a lower bounding
     convex function or an upper bounding concave function
@@ -364,7 +364,7 @@ def construct(self, pblock, x_var, y_var):
             )
 
 
-class _SOS2Piecewise(object):
+class _SOS2Piecewise:
     """
     Called to generate Piecewise constraint using the SOS2 formulation
     """
@@ -408,7 +408,7 @@ def SOS2_rule(model):
         pblock.SOS2_sosconstraint = SOSConstraint(initialize=SOS2_rule, sos=2)
 
 
-class _DCCPiecewise(object):
+class _DCCPiecewise:
     """
     Called to generate Piecewise constraint using the DCC formulation
     """
@@ -466,7 +466,7 @@ def con3_rule(model, p):
         pblock.DCC_constraint4 = Constraint(expr=sum(bin_y[p] for p in polytopes) == 1)
 
 
-class _DLOGPiecewise(object):
+class _DLOGPiecewise:
     """
     Called to generate Piecewise constraint using the DLOG formulation
     """
@@ -568,7 +568,7 @@ def con5_rule(model, l):
         pblock.DLOG_constraint5 = Constraint(bin_y_index, rule=con5_rule)
 
 
-class _CCPiecewise(object):
+class _CCPiecewise:
     """
     Called to generate Piecewise constraint using the CC formulation
     """
@@ -624,7 +624,7 @@ def con4_rule(model, v):
         pblock.CC_constraint5 = Constraint(expr=sum(bin_y[p] for p in polytopes) == 1)
 
 
-class _LOGPiecewise(object):
+class _LOGPiecewise:
     """
     Called to generate Piecewise constraint using the LOG formulation
     """
@@ -717,7 +717,7 @@ def con5_rule(model, s):
         pblock.LOG_constraint5 = Constraint(bin_y_index, rule=con5_rule)
 
 
-class _MCPiecewise(object):
+class _MCPiecewise:
     """
     Called to generate Piecewise constraint using the MC formulation
     """
@@ -774,7 +774,7 @@ def con4_rule(model, p):
         pblock.MC_constraint5 = Constraint(expr=sum(bin_y[p] for p in polytopes) == 1)
 
 
-class _INCPiecewise(object):
+class _INCPiecewise:
     """
     Called to generate Piecewise constraint using the INC formulation
     """
@@ -836,7 +836,7 @@ def con4_rule(model, p):
         pblock.INC_constraint4 = Constraint(polytopes, rule=con4_rule)
 
 
-class _BIGMPiecewise(object):
+class _BIGMPiecewise:
     """
     Called to generate Piecewise constraint using the BIGM formulation
     """
diff --git a/pyomo/core/base/range.py b/pyomo/core/base/range.py
index 98951f16439..c4c5e71b702 100644
--- a/pyomo/core/base/range.py
+++ b/pyomo/core/base/range.py
@@ -681,7 +681,7 @@ def range_intersection(self, other_ranges):
         return ans
 
 
-class NonNumericRange(object):
+class NonNumericRange:
     """A range-like object for representing a single non-numeric value
 
     The class name is a bit of a misnomer, as this object does not
@@ -758,7 +758,7 @@ def range_intersection(self, other_ranges):
         return []
 
 
-class AnyRange(object):
+class AnyRange:
     """A range object for representing Any sets"""
 
     __slots__ = ()
@@ -803,7 +803,7 @@ def range_intersection(self, other_ranges):
         return list(other_ranges)
 
 
-class RangeProduct(object):
+class RangeProduct:
     """A range-like object for representing the cross product of ranges"""
 
     __slots__ = ('range_lists',)
diff --git a/pyomo/core/base/reference.py b/pyomo/core/base/reference.py
index 3f3d71b9137..bed54c37306 100644
--- a/pyomo/core/base/reference.py
+++ b/pyomo/core/base/reference.py
@@ -44,7 +44,7 @@
 )
 
 
-class _fill_in_known_wildcards(object):
+class _fill_in_known_wildcards:
     """Variant of "six.advance_iterator" that substitutes wildcard values
 
     This object is initialized with a tuple of index values.  Calling
diff --git a/pyomo/core/base/set.py b/pyomo/core/base/set.py
index da405a4ddd9..3c00059e638 100644
--- a/pyomo/core/base/set.py
+++ b/pyomo/core/base/set.py
@@ -298,7 +298,7 @@ def A_rule(model, i, j):
     return rule_wrapper(rule, {None: Set.End})
 
 
-class UnknownSetDimen(object):
+class UnknownSetDimen:
     pass
 
 
@@ -517,7 +517,7 @@ def _tuplize(self, _val, parent, index):
         return (tuple(_val[i : i + d]) for i in range(0, len(_val), d))
 
 
-class _NotFound(object):
+class _NotFound:
     "Internal type flag used to indicate if an object is not found in a set"
 
     pass
@@ -1201,7 +1201,7 @@ class _SetDataBase(metaclass=RenamedClass):
     __renamed__version__ = '6.7.2'
 
 
-class _FiniteSetMixin(object):
+class _FiniteSetMixin:
     __slots__ = ()
 
     def __len__(self):
@@ -1607,7 +1607,7 @@ class _FiniteSetData(metaclass=RenamedClass):
     __renamed__version__ = '6.7.2'
 
 
-class _ScalarOrderedSetMixin(object):
+class _ScalarOrderedSetMixin:
     # This mixin is required because scalar ordered sets implement
     # __getitem__() as an alias of at()
     __slots__ = ()
@@ -1624,7 +1624,7 @@ def items(self):
             yield _keys[0], self
 
 
-class _OrderedSetMixin(object):
+class _OrderedSetMixin:
     __slots__ = ()
     _valid_getitem_keys = {None, (None,), Ellipsis}
 
@@ -1941,7 +1941,7 @@ class _InsertionOrderSetData(metaclass=RenamedClass):
     __renamed__version__ = '6.7.2'
 
 
-class _SortedSetMixin(object):
+class _SortedSetMixin:
     """"""
 
     __slots__ = ()
@@ -2117,10 +2117,10 @@ def __hash__(self):
     class End(metaclass=_SetEndType):
         pass
 
-    class InsertionOrder(object):
+    class InsertionOrder:
         pass
 
-    class SortedOrder(object):
+    class SortedOrder:
         pass
 
     _ValidOrderedArguments = {True, False, InsertionOrder, SortedOrder}
diff --git a/pyomo/core/base/suffix.py b/pyomo/core/base/suffix.py
index fd6b8717eec..86553552eb7 100644
--- a/pyomo/core/base/suffix.py
+++ b/pyomo/core/base/suffix.py
@@ -409,7 +409,7 @@ class AbstractSuffix(Suffix):
     pass
 
 
-class SuffixFinder(object):
+class SuffixFinder:
     def __init__(self, name, default=None, context=None):
         """This provides an efficient utility for finding suffix values on a
         (hierarchical) Pyomo model.
diff --git a/pyomo/core/base/transformation.py b/pyomo/core/base/transformation.py
index d2945d6bb66..7021b417ea1 100644
--- a/pyomo/core/base/transformation.py
+++ b/pyomo/core/base/transformation.py
@@ -17,11 +17,11 @@
 from pyomo.common.timing import TransformationTimer
 
 
-class TransformationInfo(object):
+class TransformationInfo:
     pass
 
 
-class TransformationData(object):
+class TransformationData:
     """
     This is a container class that supports named data objects.
     """
@@ -35,7 +35,7 @@ def __getitem__(self, name):
         return self._data[name]
 
 
-class Transformation(object):
+class Transformation:
     """
     Base class for all model transformations.
     """
@@ -109,7 +109,7 @@ def _create_using(self, model, **kwds):
         return instance
 
 
-class ReverseTransformationToken(object):
+class ReverseTransformationToken:
     """
     Class returned by reversible transformations' apply_to methods that
     can be passed back to the transformation in order to revert its changes
diff --git a/pyomo/core/base/units_container.py b/pyomo/core/base/units_container.py
index 96f7e85139c..f90c2295c23 100644
--- a/pyomo/core/base/units_container.py
+++ b/pyomo/core/base/units_container.py
@@ -944,7 +944,7 @@ def finalizeResult(self, result):
         return result
 
 
-class PyomoUnitsContainer(object):
+class PyomoUnitsContainer:
     """Class that is used to create and contain units in Pyomo.
 
     This is the class that is used to create, contain, and interact
diff --git a/pyomo/core/expr/base.py b/pyomo/core/expr/base.py
index 390cb447c0d..2a9ca66d29e 100644
--- a/pyomo/core/expr/base.py
+++ b/pyomo/core/expr/base.py
@@ -394,7 +394,7 @@ def _apply_operation(self, result):
         )
 
 
-class NPV_Mixin(object):
+class NPV_Mixin:
     __slots__ = ()
 
     def is_potentially_variable(self):
@@ -426,7 +426,7 @@ def potentially_variable_base_class(self):
         return cls[0]
 
 
-class ExpressionArgs_Mixin(object):
+class ExpressionArgs_Mixin:
     __slots__ = ('_args_',)
 
     def __init__(self, args):
diff --git a/pyomo/core/expr/numeric_expr.py b/pyomo/core/expr/numeric_expr.py
index 99dc4b5b0b5..01fd739c0d3 100644
--- a/pyomo/core/expr/numeric_expr.py
+++ b/pyomo/core/expr/numeric_expr.py
@@ -161,7 +161,7 @@ def enable_expression_optimizations(zero=None, one=None):
             _zero_one_optimizations.discard(key)
 
 
-class mutable_expression(object):
+class mutable_expression:
     """Context manager for mutable sums.
 
     This context manager is used to compute a sum while treating the
diff --git a/pyomo/core/expr/symbol_map.py b/pyomo/core/expr/symbol_map.py
index b0265162974..22929d40494 100644
--- a/pyomo/core/expr/symbol_map.py
+++ b/pyomo/core/expr/symbol_map.py
@@ -10,7 +10,7 @@
 #  ___________________________________________________________________________
 
 
-class SymbolMap(object):
+class SymbolMap:
     """
     A class for tracking assigned labels for modeling components.
 
diff --git a/pyomo/core/expr/sympy_tools.py b/pyomo/core/expr/sympy_tools.py
index cd92f9023ff..9eb18415e37 100644
--- a/pyomo/core/expr/sympy_tools.py
+++ b/pyomo/core/expr/sympy_tools.py
@@ -132,7 +132,7 @@ def _configure_sympy(sympy, available):
 sympy, sympy_available = attempt_import('sympy', callback=_configure_sympy)
 
 
-class PyomoSympyBimap(object):
+class PyomoSympyBimap:
     def __init__(self):
         self.pyomo2sympy = ComponentMap()
         self.sympy2pyomo = {}
diff --git a/pyomo/core/expr/template_expr.py b/pyomo/core/expr/template_expr.py
index 90d1a39292b..bab52f81c34 100644
--- a/pyomo/core/expr/template_expr.py
+++ b/pyomo/core/expr/template_expr.py
@@ -48,7 +48,7 @@
 logger = logging.getLogger(__name__)
 
 
-class _NotSpecified(object):
+class _NotSpecified:
     pass
 
 
@@ -363,7 +363,7 @@ def _resolve_template(self, args):
         return self._apply_operation(args)
 
 
-class _TemplateSumExpression_argList(object):
+class _TemplateSumExpression_argList:
     """A virtual list to represent the expanded SumExpression args
 
     This class implements a "virtual args list" for
@@ -726,7 +726,7 @@ def resolve_template(expr):
 resolve_template.visitor = None
 
 
-class _wildcard_info(object):
+class _wildcard_info:
     __slots__ = ('iter', 'source', 'value', 'original_value', 'objects')
 
     def __init__(self, src, obj):
@@ -913,7 +913,7 @@ def substitute_template_expression(expr, substituter, *args, **kwargs):
     return visitor.walk_expression(expr)
 
 
-class _GetItemIndexer(object):
+class _GetItemIndexer:
     # Note that this class makes the assumption that only one template
     # ever appears in an expression for a single index
 
@@ -1003,7 +1003,7 @@ def substitute_template_with_value(expr):
         return resolve_template(expr)
 
 
-class _set_iterator_template_generator(object):
+class _set_iterator_template_generator:
     """Replacement iterator that returns IndexTemplates
 
     In order to generate template expressions, we hijack the normal Set
@@ -1047,7 +1047,7 @@ def __next__(self):
     next = __next__
 
 
-class _template_iter_context(object):
+class _template_iter_context:
     """Manage the iteration context when generating templatized rules
 
     This class manages the context tracking when generating templatized
@@ -1086,8 +1086,8 @@ def sum_template(self, generator):
         return TemplateSumExpression((expr,), self.npop_cache(final_cache - init_cache))
 
 
-class _template_iter_manager(object):
-    class _iter_wrapper(object):
+class _template_iter_manager:
+    class _iter_wrapper:
         __slots__ = ('_class', '_iter', '_old_iter')
 
         def __init__(self, cls, context):
@@ -1104,7 +1104,7 @@ def acquire(self):
         def release(self):
             self._class.__iter__ = self._old_iter
 
-    class _pause_template_iter_manager(object):
+    class _pause_template_iter_manager:
         __slots__ = ('iter_manager',)
 
         def __init__(self, iter_manager):
diff --git a/pyomo/core/expr/visitor.py b/pyomo/core/expr/visitor.py
index 2bb80c82872..c35a08b7237 100644
--- a/pyomo/core/expr/visitor.py
+++ b/pyomo/core/expr/visitor.py
@@ -78,7 +78,7 @@ class RevertToNonrecursive(Exception):
 # -------------------------------------------------------
 
 
-class StreamBasedExpressionVisitor(object):
+class StreamBasedExpressionVisitor:
     """This class implements a generic stream-based expression walker.
 
     This visitor walks an expression tree using a depth-first strategy
@@ -684,7 +684,7 @@ def _nonrecursive_walker_loop(self, ptr):
     "Please use the StreamBasedExpressionVisitor instead.",
     version='6.9.0',
 )
-class SimpleExpressionVisitor(object):
+class SimpleExpressionVisitor:
     """
     Note:
         This class is a customization of the PyUtilib :class:`SimpleVisitor
@@ -819,7 +819,7 @@ def xbfs_yield_leaves(self, node):
                     dq.append(c)
 
 
-class ExpressionValueVisitor(object):
+class ExpressionValueVisitor:
     """
     Note:
         This class is a customization of the PyUtilib :class:`ValueVisitor
diff --git a/pyomo/core/kernel/base.py b/pyomo/core/kernel/base.py
index 60787a2fb70..38be7e661c8 100644
--- a/pyomo/core/kernel/base.py
+++ b/pyomo/core/kernel/base.py
@@ -28,7 +28,7 @@ def _abstract_readonly_property(**kwds):
     return p
 
 
-class _no_ctype(object):
+class _no_ctype:
     """The default argument for methods that accept a ctype."""
 
     pass
@@ -162,7 +162,7 @@ def getname(
                 storage key into a string
                 representation. Default is the built-in
                 function str.
-            relative_to (object): When generating a fully
+            relative_to : When generating a fully
                 qualified name, generate the name relative
                 to this block.
 
diff --git a/pyomo/core/kernel/constraint.py b/pyomo/core/kernel/constraint.py
index 120e3f3df02..35f92af6dfd 100644
--- a/pyomo/core/kernel/constraint.py
+++ b/pyomo/core/kernel/constraint.py
@@ -174,7 +174,7 @@ def to_bounded_expression(self, evaluate_bounds=False):
         return self.lower, self.body, self.upper
 
 
-class _MutableBoundsConstraintMixin(object):
+class _MutableBoundsConstraintMixin:
     """
     Use as a base class for IConstraint implementations
     that allow adjusting the lb, ub, rhs, and equality
diff --git a/pyomo/core/kernel/piecewise_library/transforms.py b/pyomo/core/kernel/piecewise_library/transforms.py
index cbdbad33380..94aa4b7a34f 100644
--- a/pyomo/core/kernel/piecewise_library/transforms.py
+++ b/pyomo/core/kernel/piecewise_library/transforms.py
@@ -57,7 +57,7 @@
 
 # wrapper that allows a list containing parameters to be
 # used with the bisect module
-class _shadow_list(object):
+class _shadow_list:
     __slots__ = ("_x",)
 
     def __init__(self, x):
@@ -214,7 +214,7 @@ def piecewise(
     )
 
 
-class PiecewiseLinearFunction(object):
+class PiecewiseLinearFunction:
     """A piecewise linear function
 
     Piecewise linear functions are defined by a list of
diff --git a/pyomo/core/kernel/piecewise_library/transforms_nd.py b/pyomo/core/kernel/piecewise_library/transforms_nd.py
index 12dd5005441..781cac3f7c0 100644
--- a/pyomo/core/kernel/piecewise_library/transforms_nd.py
+++ b/pyomo/core/kernel/piecewise_library/transforms_nd.py
@@ -101,7 +101,7 @@ def piecewise_nd(tri, values, input=None, output=None, bound='eq', repn='cc'):
     return transform(func, input=input, output=output, bound=bound)
 
 
-class PiecewiseLinearFunctionND(object):
+class PiecewiseLinearFunctionND:
     """A multi-variate piecewise linear function
 
     Multi-varite piecewise linear functions are defined by a
diff --git a/pyomo/core/kernel/set_types.py b/pyomo/core/kernel/set_types.py
index ee5ea677ee8..2a1a0de583e 100644
--- a/pyomo/core/kernel/set_types.py
+++ b/pyomo/core/kernel/set_types.py
@@ -20,7 +20,7 @@
 #
 # Dummy types used by Kernel as domain flags
 #
-class RealSet(object):
+class RealSet:
     @staticmethod
     def get_interval():
         return (None, None, 0)
@@ -38,7 +38,7 @@ def is_binary():
         return False
 
 
-class IntegerSet(object):
+class IntegerSet:
     @staticmethod
     def get_interval():
         return (None, None, 1)
@@ -56,7 +56,7 @@ def is_binary():
         return False
 
 
-class BinarySet(object):
+class BinarySet:
     @staticmethod
     def get_interval():
         return (0, 1, 1)
diff --git a/pyomo/core/plugins/transform/lp_dual.py b/pyomo/core/plugins/transform/lp_dual.py
index e2f0871dbb8..59b9949307e 100644
--- a/pyomo/core/plugins/transform/lp_dual.py
+++ b/pyomo/core/plugins/transform/lp_dual.py
@@ -47,7 +47,7 @@ def __init__(self):
 @TransformationFactory.register(
     'core.lp_dual', 'Generate the linear programming dual of the given model'
 )
-class LinearProgrammingDual(object):
+class LinearProgrammingDual:
     CONFIG = ConfigDict("core.lp_dual")
     CONFIG.declare(
         'parameterize_wrt',
diff --git a/pyomo/core/staleflag.py b/pyomo/core/staleflag.py
index 86e68e0831e..6bf9972b7bb 100644
--- a/pyomo/core/staleflag.py
+++ b/pyomo/core/staleflag.py
@@ -10,7 +10,7 @@
 #  ___________________________________________________________________________
 
 
-class _StaleFlagManager(object):
+class _StaleFlagManager:
     def __init__(self):
         self._current = 0
         self.mark_all_as_stale()
diff --git a/pyomo/core/tests/unit/kernel/test_block.py b/pyomo/core/tests/unit/kernel/test_block.py
index 2949a018f5c..8d4daefb498 100644
--- a/pyomo/core/tests/unit/kernel/test_block.py
+++ b/pyomo/core/tests/unit/kernel/test_block.py
@@ -1341,7 +1341,7 @@ def test_ordering(self):
             objs.rotate(-1)
 
 
-class _Test_block_base(object):
+class _Test_block_base:
     _children = None
     _child_key = None
     _components_no_descend = None
diff --git a/pyomo/core/tests/unit/kernel/test_conic.py b/pyomo/core/tests/unit/kernel/test_conic.py
index a5e228bc9e7..c558bc82def 100644
--- a/pyomo/core/tests/unit/kernel/test_conic.py
+++ b/pyomo/core/tests/unit/kernel/test_conic.py
@@ -40,7 +40,7 @@
 )
 
 
-class _conic_tester_base(object):
+class _conic_tester_base:
     _object_factory = None
 
     def setUp(self):
diff --git a/pyomo/core/tests/unit/kernel/test_dict_container.py b/pyomo/core/tests/unit/kernel/test_dict_container.py
index 1cacc024099..d0154ffaf2b 100644
--- a/pyomo/core/tests/unit/kernel/test_dict_container.py
+++ b/pyomo/core/tests/unit/kernel/test_dict_container.py
@@ -36,11 +36,11 @@
 _pickle_test_protocol = pickle.HIGHEST_PROTOCOL
 
 
-class _bad_ctype(object):
+class _bad_ctype:
     ctype = "_this_is_definitely_not_the_ctype_being_tested"
 
 
-class _TestDictContainerBase(object):
+class _TestDictContainerBase:
     # set by derived class
     _container_type = None
     _ctype_factory = None
diff --git a/pyomo/core/tests/unit/kernel/test_expression.py b/pyomo/core/tests/unit/kernel/test_expression.py
index 7ddbfea4f67..08d7c69e1e6 100644
--- a/pyomo/core/tests/unit/kernel/test_expression.py
+++ b/pyomo/core/tests/unit/kernel/test_expression.py
@@ -305,7 +305,7 @@ def test_to_string(self):
         del b.p
 
 
-class _Test_expression_base(object):
+class _Test_expression_base:
     _ctype_factory = None
 
     def test_pprint(self):
diff --git a/pyomo/core/tests/unit/kernel/test_list_container.py b/pyomo/core/tests/unit/kernel/test_list_container.py
index a4e8ae5054e..d947c96e4a8 100644
--- a/pyomo/core/tests/unit/kernel/test_list_container.py
+++ b/pyomo/core/tests/unit/kernel/test_list_container.py
@@ -35,11 +35,11 @@
 _pickle_test_protocol = pickle.HIGHEST_PROTOCOL
 
 
-class _bad_ctype(object):
+class _bad_ctype:
     ctype = "_this_is_definitely_not_the_ctype_being_tested"
 
 
-class _TestListContainerBase(object):
+class _TestListContainerBase:
     # set by derived class
     _container_type = None
     _ctype_factory = None
diff --git a/pyomo/core/tests/unit/kernel/test_tuple_container.py b/pyomo/core/tests/unit/kernel/test_tuple_container.py
index 2190ff5d2f7..eb6f60e0751 100644
--- a/pyomo/core/tests/unit/kernel/test_tuple_container.py
+++ b/pyomo/core/tests/unit/kernel/test_tuple_container.py
@@ -33,11 +33,11 @@
 _pickle_test_protocol = pickle.HIGHEST_PROTOCOL
 
 
-class _bad_ctype(object):
+class _bad_ctype:
     ctype = "_this_is_definitely_not_the_ctype_being_tested"
 
 
-class _TestTupleContainerBase(object):
+class _TestTupleContainerBase:
     # set by derived class
     _container_type = None
     _ctype_factory = None
diff --git a/pyomo/core/tests/unit/test_block.py b/pyomo/core/tests/unit/test_block.py
index 55fb5850635..e8e768cfa8c 100644
--- a/pyomo/core/tests/unit/test_block.py
+++ b/pyomo/core/tests/unit/test_block.py
@@ -474,7 +474,7 @@ def test_mixed_index_type(self):
             self.assertIs(a, b)
 
 
-class HierarchicalModel(object):
+class HierarchicalModel:
     def __init__(self):
         m = self.model = ConcreteModel()
         m.a1_IDX = Set(initialize=[5, 4], ordered=True)
@@ -671,7 +671,7 @@ def a(b, i):
         ]
 
 
-class MixedHierarchicalModel(object):
+class MixedHierarchicalModel:
     def __init__(self):
         m = self.model = ConcreteModel()
         m.a = Block()
@@ -2533,7 +2533,7 @@ def d(b, i):
             self.assertIs(m.d[i].parent_block(), m)
 
     def test_clone_unclonable_attribute(self):
-        class foo(object):
+        class foo:
             def __deepcopy__(bogus):
                 pass
 
diff --git a/pyomo/core/tests/unit/test_component.py b/pyomo/core/tests/unit/test_component.py
index 1ac11e92fdf..4f2e4507808 100644
--- a/pyomo/core/tests/unit/test_component.py
+++ b/pyomo/core/tests/unit/test_component.py
@@ -105,7 +105,7 @@ def test_component_data_pprint(self):
     def test_is_reference(self):
         m = ConcreteModel()
 
-        class _NotSpecified(object):
+        class _NotSpecified:
             pass
 
         m.comp = Component(ctype=_NotSpecified)
diff --git a/pyomo/core/tests/unit/test_dict_objects.py b/pyomo/core/tests/unit/test_dict_objects.py
index 9f8849cc2b5..0c15c5faf86 100644
--- a/pyomo/core/tests/unit/test_dict_objects.py
+++ b/pyomo/core/tests/unit/test_dict_objects.py
@@ -23,7 +23,7 @@
 from pyomo.core.base.expression import ExpressionData
 
 
-class _TestComponentDictBase(object):
+class _TestComponentDictBase:
     _ctype = None
     _cdatatype = None
 
diff --git a/pyomo/core/tests/unit/test_disable_methods.py b/pyomo/core/tests/unit/test_disable_methods.py
index 67dfed01cae..5be41914a92 100644
--- a/pyomo/core/tests/unit/test_disable_methods.py
+++ b/pyomo/core/tests/unit/test_disable_methods.py
@@ -17,7 +17,7 @@
 from pyomo.common.modeling import NOTSET
 
 
-class LocalClass(object):
+class LocalClass:
     def __init__(self, name):
         self._name = name
 
@@ -28,7 +28,7 @@ def __str__(self):
 local_instance = LocalClass('local')
 
 
-class _simple(object):
+class _simple:
     def __init__(self, name):
         self.name = name
         self._d = 'd'
diff --git a/pyomo/core/tests/unit/test_initializer.py b/pyomo/core/tests/unit/test_initializer.py
index 4a4f683b33a..041ba69e8a2 100644
--- a/pyomo/core/tests/unit/test_initializer.py
+++ b/pyomo/core/tests/unit/test_initializer.py
@@ -228,7 +228,7 @@ def bogus(m, i, j):
         self.assertEqual(next(c), 335)
 
     def test_method(self):
-        class Init(object):
+        class Init:
             def a_init(self, m):
                 return 0
 
@@ -288,7 +288,7 @@ def y_init(self, m, i, j):
         self.assertEqual(next(c), 40)
 
     def test_classmethod(self):
-        class Init(object):
+        class Init:
             @classmethod
             def a_init(cls, m):
                 return 0
@@ -350,7 +350,7 @@ def y_init(cls, m, i, j):
         self.assertEqual(next(c), 40)
 
     def test_staticmethod(self):
-        class Init(object):
+        class Init:
             @staticmethod
             def a_init(m):
                 return 0
@@ -446,7 +446,7 @@ def y_init(m, i, j):
         self.assertEqual(list(a(None, (1, 4))), [4, 2])
 
     def test_generator_method(self):
-        class Init(object):
+        class Init:
             def a_init(self, m):
                 yield 0
                 yield 3
@@ -506,7 +506,7 @@ def x_init():
         self.assertEqual(list(a(None, 1)), [0, 3])
 
     def test_functor(self):
-        class InitScalar(object):
+        class InitScalar:
             def __init__(self, val):
                 self.val = val
 
@@ -519,7 +519,7 @@ def __call__(self, m):
         self.assertFalse(a.verified)
         self.assertEqual(a(None, None), 10)
 
-        class InitIndexed(object):
+        class InitIndexed:
             def __init__(self, val):
                 self.val = val
 
@@ -900,7 +900,7 @@ def a_init(m):
         self.assertIs(type(a), ParameterizedIndexedCallInitializer)
         self.assertEqual(a('m', 1, 5), ('m', 5, 1))
 
-        class Functor(object):
+        class Functor:
             def __init__(self, i):
                 self.i = i
 
diff --git a/pyomo/core/tests/unit/test_list_objects.py b/pyomo/core/tests/unit/test_list_objects.py
index 379808aeb61..ed1742beb9d 100644
--- a/pyomo/core/tests/unit/test_list_objects.py
+++ b/pyomo/core/tests/unit/test_list_objects.py
@@ -23,7 +23,7 @@
 from pyomo.core.base.expression import ExpressionData
 
 
-class _TestComponentListBase(object):
+class _TestComponentListBase:
     _ctype = None
     _cdatatype = None
 
diff --git a/pyomo/core/tests/unit/test_numeric_expr.py b/pyomo/core/tests/unit/test_numeric_expr.py
index 5e35d4b6513..8a854141c68 100644
--- a/pyomo/core/tests/unit/test_numeric_expr.py
+++ b/pyomo/core/tests/unit/test_numeric_expr.py
@@ -118,7 +118,7 @@
 from pyomo.core.expr.numvalue import NumericValue
 
 
-class decompose_linear_term_wrapper(object):
+class decompose_linear_term_wrapper:
     def __init__(self, pairs):
         self.pairs = pairs
 
diff --git a/pyomo/core/tests/unit/test_numeric_expr_api.py b/pyomo/core/tests/unit/test_numeric_expr_api.py
index 9c5775432e9..fc0a1e6f121 100644
--- a/pyomo/core/tests/unit/test_numeric_expr_api.py
+++ b/pyomo/core/tests/unit/test_numeric_expr_api.py
@@ -58,7 +58,7 @@
 from pyomo.environ import ConcreteModel, Param, Var, ExternalFunction
 
 
-class MockExternalFunction(object):
+class MockExternalFunction:
     def evaluate(self, args):
         (x,) = args
         return (math.log(x) / math.log(2)) ** 2
diff --git a/pyomo/core/tests/unit/test_numeric_expr_dispatcher.py b/pyomo/core/tests/unit/test_numeric_expr_dispatcher.py
index 48e70781022..16e9a48b269 100644
--- a/pyomo/core/tests/unit/test_numeric_expr_dispatcher.py
+++ b/pyomo/core/tests/unit/test_numeric_expr_dispatcher.py
@@ -59,7 +59,7 @@
 logger = logging.getLogger(__name__)
 
 
-class Base(object):
+class Base:
     class SKIP:
         pass
 
diff --git a/pyomo/core/tests/unit/test_numvalue.py b/pyomo/core/tests/unit/test_numvalue.py
index 1466c7bcb49..bf007a9b844 100644
--- a/pyomo/core/tests/unit/test_numvalue.py
+++ b/pyomo/core/tests/unit/test_numvalue.py
@@ -44,7 +44,7 @@
 from pyomo.common.numeric_types import _native_boolean_types
 
 
-class MyBogusType(object):
+class MyBogusType:
     def __init__(self, val=0):
         self.val = float(val)
 
@@ -84,7 +84,7 @@ def test_NumericValue(self):
         self.assertEqual(is_numeric_data(NumericConstant(1.0)), True)
 
     def test_error(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -170,7 +170,7 @@ def test_var2(self):
         self.assertEqual(None, value(m.x, exception=False))
 
     def test_error1(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -262,7 +262,7 @@ def test_var1(self):
         self.assertTrue(1, polynomial_degree(m.x))
 
     def test_error1(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -311,7 +311,7 @@ def test_const2(self):
         self.assertTrue(is_constant(val))
 
     def test_error(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -354,7 +354,7 @@ def test_const1(self):
         self.assertTrue(is_fixed(val))
 
     def test_error(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -397,7 +397,7 @@ def test_const1(self):
         self.assertFalse(is_variable_type(val))
 
     def test_error(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -433,7 +433,7 @@ def test_const1(self):
         self.assertFalse(is_potentially_variable(val))
 
     def test_error(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
@@ -499,7 +499,7 @@ def test_const1(self):
         self.assertEqual(1.0, as_numeric(val))
 
     def test_error1(self):
-        class A(object):
+        class A:
             pass
 
         val = A()
diff --git a/pyomo/core/tests/unit/test_param.py b/pyomo/core/tests/unit/test_param.py
index 66fbb742b70..3903a09fef0 100644
--- a/pyomo/core/tests/unit/test_param.py
+++ b/pyomo/core/tests/unit/test_param.py
@@ -74,7 +74,7 @@
 NoValue = Param.NoValue
 
 
-class ParamTester(object):
+class ParamTester:
     def setUp(self, **kwds):
         #
         # Sparse single-index Param, no default
diff --git a/pyomo/core/tests/unit/test_range.py b/pyomo/core/tests/unit/test_range.py
index cb4399beb22..cb4ed26cbcf 100644
--- a/pyomo/core/tests/unit/test_range.py
+++ b/pyomo/core/tests/unit/test_range.py
@@ -235,7 +235,7 @@ def test_contains(self):
         self.assertNotIn({0: -1}, NR(0, None, 0))
         self.assertNotIn({1: 1}, NR(0, None, 0))
 
-        class _Unrelated(object):
+        class _Unrelated:
             pass
 
         self.assertNotIn(_Unrelated(), NR(0, None, 0))
@@ -270,7 +270,7 @@ def __ne__(self, other):
         self.assertNotIn(_NotCastable(1), NR(0, None, 0))
         self.assertNotIn(_NotCastable, NR._types_comparable_to_int)
 
-        class _Custom(object):
+        class _Custom:
             def __init__(self, val):
                 self.val = val
 
diff --git a/pyomo/core/tests/unit/test_reference.py b/pyomo/core/tests/unit/test_reference.py
index adeb0a52caa..50d04b02adb 100644
--- a/pyomo/core/tests/unit/test_reference.py
+++ b/pyomo/core/tests/unit/test_reference.py
@@ -652,7 +652,7 @@ def test_constructor_error(self):
         m = ConcreteModel()
         m.x = Var([1, 2])
 
-        class Foo(object):
+        class Foo:
             pass
 
         self.assertRaisesRegex(
diff --git a/pyomo/core/tests/unit/test_set.py b/pyomo/core/tests/unit/test_set.py
index ea4931f9767..f9e01b217fa 100644
--- a/pyomo/core/tests/unit/test_set.py
+++ b/pyomo/core/tests/unit/test_set.py
@@ -955,7 +955,7 @@ def test_constructor(self):
         )
         self.assertEqual(RangeSet(0, 5, 1), m.I)
 
-        class _AlmostNumeric(object):
+        class _AlmostNumeric:
             def __init__(self, val):
                 self.val = val
 
@@ -1228,7 +1228,7 @@ def test_equality(self):
 
         # It can even work for non-iterable objects (that can't be cast
         # to set())
-        class _NonIterable(object):
+        class _NonIterable:
             def __init__(self):
                 self.data = set({1, 3, 5})
 
@@ -1410,7 +1410,7 @@ def test_isdisjoint(self):
 
         # It can even work for non-iterable objects (that can't be cast
         # to set())
-        class _NonIterable(object):
+        class _NonIterable:
             def __init__(self):
                 self.data = set({1, 3, 5})
 
@@ -1453,7 +1453,7 @@ def test_issubset(self):
 
         # It can even work for non-iterable objects (that can't be cast
         # to set())
-        class _NonIterable(object):
+        class _NonIterable:
             def __init__(self):
                 self.data = set({1, 3, 5})
 
@@ -1496,7 +1496,7 @@ def test_issuperset(self):
 
         # But NOT non-iterable objects: we assume that everything that
         # does not implement isfinite() is a discrete set.
-        class _NonIterable(object):
+        class _NonIterable:
             def __init__(self):
                 self.data = set({1, 3, 5})
 
diff --git a/pyomo/core/tests/unit/test_smap.py b/pyomo/core/tests/unit/test_smap.py
index 0394f986602..8b1041930fe 100644
--- a/pyomo/core/tests/unit/test_smap.py
+++ b/pyomo/core/tests/unit/test_smap.py
@@ -154,7 +154,7 @@ def test_error1(self):
         labeler = TextLabeler()
         self.assertEqual('x', smap.getSymbol(self.instance.x, labeler))
 
-        class FOO(object):
+        class FOO:
             def __call__(self, *args):
                 return 'x'
 
diff --git a/pyomo/core/tests/unit/test_sos_v2.py b/pyomo/core/tests/unit/test_sos_v2.py
index 32e10933fb4..49d95d26784 100644
--- a/pyomo/core/tests/unit/test_sos_v2.py
+++ b/pyomo/core/tests/unit/test_sos_v2.py
@@ -28,7 +28,7 @@
 
 
 @unittest.skipIf(not solver_available, "The solver is not available.")
-class SOSProblem_nonindexed(object):
+class SOSProblem_nonindexed:
     "Test non-indexed SOS using a single pyomo Var component."
 
     def verify(
@@ -505,7 +505,7 @@ def test(self):
 
 
 @unittest.skipIf(not solver_available, "The solver is not available.")
-class SOSProblem_nonindexed_multivar(object):
+class SOSProblem_nonindexed_multivar:
     "Test non-indexed SOS made up of different Var components."
 
     def verify(self, model, sos, exp_res, abs_tol, show_output: bool = False):
@@ -599,7 +599,7 @@ def test(self):
 
 
 @unittest.skipIf(not solver_available, "The solver is not available.")
-class SOSProblem_indexed(object):
+class SOSProblem_indexed:
     "Test indexed SOS using a single pyomo Var component."
 
     def verify(
@@ -970,7 +970,7 @@ def test(self):
 
 
 @unittest.skipIf(not solver_available, "The solver is not available.")
-class SOSProblem_indexedmultivar(object):
+class SOSProblem_indexedmultivar:
     "Test indexed SOS made up of different Var components."
 
     def verify(self, model, sos, exp_res, abs_tol, show_output: bool = False):
diff --git a/pyomo/core/tests/unit/test_symbolic.py b/pyomo/core/tests/unit/test_symbolic.py
index 30bd9120882..862aab080b0 100644
--- a/pyomo/core/tests/unit/test_symbolic.py
+++ b/pyomo/core/tests/unit/test_symbolic.py
@@ -395,7 +395,7 @@ def test_errors(self):
 
         obj_map = PyomoSympyBimap()
 
-        class bogus(object):
+        class bogus:
             def __init__(self):
                 self.args = (obj_map.getSympySymbol(m.x),)
                 self.func = type(self)
diff --git a/pyomo/core/tests/unit/test_units.py b/pyomo/core/tests/unit/test_units.py
index 88d40ff81b7..4d5296585db 100644
--- a/pyomo/core/tests/unit/test_units.py
+++ b/pyomo/core/tests/unit/test_units.py
@@ -1146,7 +1146,7 @@ def test_as_quantity_scalar(self):
         self.assertIs(q.__class__, bool)
         self.assertEqual(q, True)
 
-        class UnknownPyomoType(object):
+        class UnknownPyomoType:
             def is_expression_type(self, expression_system=None):
                 return False
 
diff --git a/pyomo/core/tests/unit/test_visitor.py b/pyomo/core/tests/unit/test_visitor.py
index 07c5fb5c03b..49f59f616e0 100644
--- a/pyomo/core/tests/unit/test_visitor.py
+++ b/pyomo/core/tests/unit/test_visitor.py
@@ -1070,7 +1070,7 @@ def test_npv_abs(self):
         assertExpressionsEqual(self, e3, abs(m.x))
 
 
-class BaseStreamBasedVisitorTests(object):
+class BaseStreamBasedVisitorTests:
     def setUp(self):
         self.m = m = ConcreteModel()
         m.x = Var()
diff --git a/pyomo/dae/flatten.py b/pyomo/dae/flatten.py
index 587013002ae..6c6905cbfbf 100644
--- a/pyomo/dae/flatten.py
+++ b/pyomo/dae/flatten.py
@@ -43,7 +43,7 @@ def get_slice_for_set(s):
         return None
 
 
-class _NotAnIndex(object):
+class _NotAnIndex:
     """
     `None` is a valid index, so we use a dummy class to
     denote a slot that needs to get filled with indices
diff --git a/pyomo/dae/tests/test_flatten.py b/pyomo/dae/tests/test_flatten.py
index 3825416c341..eaae74962ef 100644
--- a/pyomo/dae/tests/test_flatten.py
+++ b/pyomo/dae/tests/test_flatten.py
@@ -29,7 +29,7 @@
 )
 
 
-class _TestFlattenBase(object):
+class _TestFlattenBase:
     """A base class to hold the common _hashRef utility method.
     We don't just derive from Test... classes directly as this
     causes tests to run twice.
diff --git a/pyomo/dataportal/DataPortal.py b/pyomo/dataportal/DataPortal.py
index 5da1ab77835..0d7720c146a 100644
--- a/pyomo/dataportal/DataPortal.py
+++ b/pyomo/dataportal/DataPortal.py
@@ -16,7 +16,7 @@
 logger = logging.getLogger('pyomo.core')
 
 
-class DataPortal(object):
+class DataPortal:
     """
     An object that manages loading and storing data from external
     data sources.  This object interfaces to plugins that manipulate
diff --git a/pyomo/dataportal/TableData.py b/pyomo/dataportal/TableData.py
index b72bdb9f2ac..75b79c9f5d4 100644
--- a/pyomo/dataportal/TableData.py
+++ b/pyomo/dataportal/TableData.py
@@ -13,7 +13,7 @@
 from pyomo.dataportal.process_data import _process_data
 
 
-class TableData(object):
+class TableData:
     """
     A class used to read/write data from/to a table in an external
     data source.
diff --git a/pyomo/dataportal/factory.py b/pyomo/dataportal/factory.py
index 2b8bb1d0d8d..94e4f1b5270 100644
--- a/pyomo/dataportal/factory.py
+++ b/pyomo/dataportal/factory.py
@@ -16,7 +16,7 @@
 logger = logging.getLogger('pyomo.core')
 
 
-class UnknownDataManager(object):
+class UnknownDataManager:
     def __init__(self, *args, **kwds):
         #
         # The 'type' is the class type of the solver instance
diff --git a/pyomo/dataportal/plugins/datacommands.py b/pyomo/dataportal/plugins/datacommands.py
index b2c020a89a4..79e9b9003bf 100644
--- a/pyomo/dataportal/plugins/datacommands.py
+++ b/pyomo/dataportal/plugins/datacommands.py
@@ -17,7 +17,7 @@
 
 
 @DataManagerFactory.register("dat", "Pyomo data command file interface")
-class PyomoDataCommands(object):
+class PyomoDataCommands:
     def __init__(self):
         self._info = []
         self.options = Bunch()
diff --git a/pyomo/dataportal/plugins/json_dict.py b/pyomo/dataportal/plugins/json_dict.py
index 844a2d7017a..d0141e46f07 100644
--- a/pyomo/dataportal/plugins/json_dict.py
+++ b/pyomo/dataportal/plugins/json_dict.py
@@ -90,7 +90,7 @@ def tuplize(d):
 
 
 @DataManagerFactory.register("json", "JSON file interface")
-class JSONDictionary(object):
+class JSONDictionary:
     def __init__(self):
         self._info = {}
         self.options = Bunch()
@@ -179,7 +179,7 @@ def clear(self):
 
 
 @DataManagerFactory.register("yaml", "YAML file interface")
-class YamlDictionary(object):
+class YamlDictionary:
     def __init__(self):
         self._info = {}
         self.options = Bunch()
diff --git a/pyomo/dataportal/tests/test_dataportal.py b/pyomo/dataportal/tests/test_dataportal.py
index f2f1dcff460..3c682c23502 100644
--- a/pyomo/dataportal/tests/test_dataportal.py
+++ b/pyomo/dataportal/tests/test_dataportal.py
@@ -1561,7 +1561,7 @@ def create_options(self, name):
         }
 
 
-class LoadTests(object):
+class LoadTests:
     skiplist = []
 
     #
diff --git a/pyomo/duality/tests/test_linear_dual.py b/pyomo/duality/tests/test_linear_dual.py
index 7a0d616ee21..40467ab7e92 100644
--- a/pyomo/duality/tests/test_linear_dual.py
+++ b/pyomo/duality/tests/test_linear_dual.py
@@ -29,7 +29,7 @@
 solver = None
 
 
-class CommonTests(object):
+class CommonTests:
     solve = True
 
     def run_bilevel(self, *_args, **kwds):
diff --git a/pyomo/environ/tests/test_environ.py b/pyomo/environ/tests/test_environ.py
index 49ff6da23fb..de40c979e5f 100644
--- a/pyomo/environ/tests/test_environ.py
+++ b/pyomo/environ/tests/test_environ.py
@@ -19,7 +19,7 @@
 import pyomo.common.unittest as unittest
 
 
-class ImportData(object):
+class ImportData:
     def __init__(self):
         self.tpl = {}
         self.pyomo = {}
diff --git a/pyomo/gdp/disjunct.py b/pyomo/gdp/disjunct.py
index 311edc77388..fd2f0c5afd6 100644
--- a/pyomo/gdp/disjunct.py
+++ b/pyomo/gdp/disjunct.py
@@ -384,7 +384,7 @@ def setub(self, arg):
 
 # The following should eventually be promoted so that all
 # IndexedComponents can use it
-class _Initializer(object):
+class _Initializer:
     """A simple function to process an argument to a Component constructor.
 
     This checks the incoming initializer type and maps it to a static
diff --git a/pyomo/gdp/plugins/bigm_mixin.py b/pyomo/gdp/plugins/bigm_mixin.py
index 4899551f918..df0ff2f6eeb 100644
--- a/pyomo/gdp/plugins/bigm_mixin.py
+++ b/pyomo/gdp/plugins/bigm_mixin.py
@@ -90,7 +90,7 @@ def _warn_for_unused_bigM_args(bigM, used_args, logger):
             logger.warning(warning_msg)
 
 
-class _BigM_MixIn(object):
+class _BigM_MixIn:
     def _get_bigM_arg_list(self, bigm_args, block):
         # Gather what we know about blocks from args exactly once. We'll still
         # check for constraints in the moment, but if that fails, we've
diff --git a/pyomo/gdp/util.py b/pyomo/gdp/util.py
index 3bfc0833a73..d1fda20a316 100644
--- a/pyomo/gdp/util.py
+++ b/pyomo/gdp/util.py
@@ -43,15 +43,15 @@
 )
 
 
-class NORMAL(object):
+class NORMAL:
     pass
 
 
-class INFEASIBLE(object):
+class INFEASIBLE:
     pass
 
 
-class NONOPTIMAL(object):
+class NONOPTIMAL:
     pass
 
 
diff --git a/pyomo/mpec/tests/test_complementarity.py b/pyomo/mpec/tests/test_complementarity.py
index 7beb5780bbc..641c071e075 100644
--- a/pyomo/mpec/tests/test_complementarity.py
+++ b/pyomo/mpec/tests/test_complementarity.py
@@ -42,7 +42,7 @@
 currdir = this_file_dir()
 
 
-class CCTests(object):
+class CCTests:
     @classmethod
     def setUpClass(cls):
         import pyomo.environ
diff --git a/pyomo/neos/kestrel.py b/pyomo/neos/kestrel.py
index 9c1695c1e15..db7aaba61b6 100644
--- a/pyomo/neos/kestrel.py
+++ b/pyomo/neos/kestrel.py
@@ -35,7 +35,7 @@
 _email_re = re.compile(r'([^@]+@[^@]+\.[a-zA-Z0-9]+)$')
 
 
-class NEOS(object):
+class NEOS:
     # NEOS currently only supports HTTPS access
     scheme = 'https'
     host = 'neos-server.org'
@@ -79,7 +79,7 @@ def make_connection(self, host):
     return ProxiedTransport_PY3()
 
 
-class kestrelAMPL(object):
+class kestrelAMPL:
     def __init__(self):
         self.setup_connection()
 
diff --git a/pyomo/neos/tests/test_neos.py b/pyomo/neos/tests/test_neos.py
index 3ebc6ebb8f3..2a97fd67366 100644
--- a/pyomo/neos/tests/test_neos.py
+++ b/pyomo/neos/tests/test_neos.py
@@ -107,7 +107,7 @@ def test_check_all_ampl_solvers(self):
                 self.fail(f"RunAllNEOSSolvers missing test for '{solver}'")
 
 
-class RunAllNEOSSolvers(object):
+class RunAllNEOSSolvers:
     def test_baron(self):
         self._run('baron')
 
@@ -192,7 +192,7 @@ def test_lgo(self):
         self._run('lgo')
 
 
-class DirectDriver(object):
+class DirectDriver:
     def _run(self, opt, constrained=True):
         m = _model(self.sense)
         with pyo.SolverManagerFactory('neos') as solver_manager:
@@ -213,7 +213,7 @@ def _run(self, opt, constrained=True):
         self.assertAlmostEqual(pyo.value(m.y), expected_y, delta=1e-5)
 
 
-class PyomoCommandDriver(object):
+class PyomoCommandDriver:
     def _run(self, opt, constrained=True):
         expected_y = {
             (pyo.minimize, True): -1,
diff --git a/pyomo/network/foqus_graph.py b/pyomo/network/foqus_graph.py
index 6fc9f75d07b..fedf6889c74 100644
--- a/pyomo/network/foqus_graph.py
+++ b/pyomo/network/foqus_graph.py
@@ -81,7 +81,7 @@
 logger = logging.getLogger('pyomo.network')
 
 
-class FOQUSGraph(object):
+class FOQUSGraph:
     def solve_tear_direct(
         self, G, order, function, tears, outEdges, iterLim, tol, tol_type, report_diffs
     ):
diff --git a/pyomo/opt/base/problem.py b/pyomo/opt/base/problem.py
index 7b1b9e8f9f6..3415e2f9bce 100644
--- a/pyomo/opt/base/problem.py
+++ b/pyomo/opt/base/problem.py
@@ -15,7 +15,7 @@
 WriterFactory = Factory('problem writer')
 
 
-class AbstractProblemWriter(object):
+class AbstractProblemWriter:
     """Base class that can write optimization problems."""
 
     def __init__(self, problem_format):  # pragma:nocover
@@ -36,7 +36,7 @@ def __exit__(self, t, v, traceback):
         pass
 
 
-class BranchDirection(object):
+class BranchDirection:
     """Allowed values for MIP variable branching directions in the `direction` Suffix of a model."""
 
     default = 0
diff --git a/pyomo/opt/base/results.py b/pyomo/opt/base/results.py
index 8e11d205032..9fe4749b413 100644
--- a/pyomo/opt/base/results.py
+++ b/pyomo/opt/base/results.py
@@ -15,7 +15,7 @@
 ReaderFactory = Factory('problem reader')
 
 
-class AbstractResultsReader(object):
+class AbstractResultsReader:
     """Base class that can read optimization results."""
 
     def __init__(self, results_format):
diff --git a/pyomo/opt/base/solvers.py b/pyomo/opt/base/solvers.py
index 767f62d07c2..004359c2ba0 100644
--- a/pyomo/opt/base/solvers.py
+++ b/pyomo/opt/base/solvers.py
@@ -54,7 +54,7 @@ def _extract_version(x, length=4):
     return None  # (0,0,0,0)[:length]
 
 
-class UnknownSolver(object):
+class UnknownSolver:
     def __init__(self, *args, **kwds):
         # super(UnknownSolver,self).__init__(**kwds)
 
@@ -236,7 +236,7 @@ def _raise_ephemeral_error(name, keyword=""):
     )
 
 
-class OptSolver(object):
+class OptSolver:
     """A generic optimization solver"""
 
     #
diff --git a/pyomo/opt/parallel/manager.py b/pyomo/opt/parallel/manager.py
index add77029e4a..a38f1f02144 100644
--- a/pyomo/opt/parallel/manager.py
+++ b/pyomo/opt/parallel/manager.py
@@ -44,7 +44,7 @@ def __init__(self, *args, **kargs):
         Exception.__init__(self, *args, **kargs)  # pragma:nocover
 
 
-class ActionHandle(object):
+class ActionHandle:
     id_counter = 0
 
     def __init__(self, error=False, explanation=""):
@@ -85,7 +85,7 @@ def __str__(self):
 FailedActionHandle = ActionHandle(error=True)
 
 
-class AsynchronousActionManager(object):
+class AsynchronousActionManager:
     @staticmethod
     def _flatten(*args):
         ahs = set()
diff --git a/pyomo/opt/problem/ampl.py b/pyomo/opt/problem/ampl.py
index a7bfcade2d3..1c42eb9cb54 100644
--- a/pyomo/opt/problem/ampl.py
+++ b/pyomo/opt/problem/ampl.py
@@ -19,7 +19,7 @@
 from pyomo.opt.base import ProblemFormat, convert_problem, guess_format
 
 
-class AmplModel(object):
+class AmplModel:
     """
     A class that provides a wrapper for AMPL models.
     """
diff --git a/pyomo/opt/results/container.py b/pyomo/opt/results/container.py
index 57cbf8a594e..4df454ea507 100644
--- a/pyomo/opt/results/container.py
+++ b/pyomo/opt/results/container.py
@@ -37,7 +37,7 @@ def __str__(self):
 strict = False
 
 
-class UndefinedData(object):
+class UndefinedData:
     singleton = {}
 
     def __new__(cls, name='undefined'):
@@ -61,7 +61,7 @@ def __str__(self):
 ignore = UndefinedData('ignore')
 
 
-class ScalarData(object):
+class ScalarData:
     def __init__(
         self,
         value=undefined,
@@ -175,7 +175,7 @@ def load(self, repn):
 #
 # This class manages a list of MapContainer objects.
 #
-class ListContainer(object):
+class ListContainer:
     def __init__(self, cls):
         self._cls = cls
         self._list = []
diff --git a/pyomo/opt/tests/base/test_convert.py b/pyomo/opt/tests/base/test_convert.py
index fd23ac3719e..8c2b13181e4 100644
--- a/pyomo/opt/tests/base/test_convert.py
+++ b/pyomo/opt/tests/base/test_convert.py
@@ -28,7 +28,7 @@
 old_tempdir = TempfileManager.tempdir
 
 
-class MockArg(object):
+class MockArg:
     def __init__(self):
         pass
 
diff --git a/pyomo/repn/ampl.py b/pyomo/repn/ampl.py
index 26bc932fa82..84c0a7e6601 100644
--- a/pyomo/repn/ampl.py
+++ b/pyomo/repn/ampl.py
@@ -75,7 +75,7 @@ def _create_strict_inequality_map(vars_):
     }
 
 
-class TextNLDebugTemplate(object):
+class TextNLDebugTemplate:
     unary = {
         'log': 'o43\t#log\n',
         'log10': 'o42\t#log10\n',
@@ -181,7 +181,7 @@ class TextNLTemplate(TextNLDebugTemplate):
     _create_strict_inequality_map(vars())
 
 
-class NLFragment(object):
+class NLFragment:
     """This is a mock "component" for the nl portion of a named Expression.
 
     It is used internally in the writer when requesting symbolic solver
@@ -201,7 +201,7 @@ def name(self):
         return 'nl(' + self._node.name + ')'
 
 
-class AMPLRepn(object):
+class AMPLRepn:
     """The "compiled" representation of an expression in AMPL NL format.
 
     This stores a compiled form of an expression in the AMPL "NL"
diff --git a/pyomo/repn/linear.py b/pyomo/repn/linear.py
index 6d88cf3e082..17d6ef86881 100644
--- a/pyomo/repn/linear.py
+++ b/pyomo/repn/linear.py
@@ -85,7 +85,7 @@ def _merge_dict(dest_dict, mult, src_dict):
                 dest_dict[vid] = mult * coef
 
 
-class LinearRepn(object):
+class LinearRepn:
     __slots__ = ("multiplier", "constant", "linear", "nonlinear")
 
     def __init__(self):
diff --git a/pyomo/repn/plugins/ampl/ampl_.py b/pyomo/repn/plugins/ampl/ampl_.py
index adb9294b2a7..73418e1a512 100644
--- a/pyomo/repn/plugins/ampl/ampl_.py
+++ b/pyomo/repn/plugins/ampl/ampl_.py
@@ -201,7 +201,7 @@ def _get_bound(exp):
     raise ValueError("non-fixed bound or weight: " + str(exp))
 
 
-class StopWatch(object):
+class StopWatch:
     def __init__(self):
         self.start = time.time()
 
@@ -212,7 +212,7 @@ def reset(self):
         self.start = time.time()
 
 
-class _Counter(object):
+class _Counter:
     def __init__(self, start):
         self._id = start
 
@@ -222,8 +222,8 @@ def __call__(self, obj):
         return tmp
 
 
-class ModelSOS(object):
-    class AmplSuffix(object):
+class ModelSOS:
+    class AmplSuffix:
         def __init__(self, name):
             self.name = name
             self.ids = []
@@ -310,7 +310,7 @@ def count_constraint(self, soscondata):
             self.ref.add(ID, weight)
 
 
-class RepnWrapper(object):
+class RepnWrapper:
     __slots__ = ('repn', 'linear_vars', 'nonlinear_vars')
 
     def __init__(self, repn, linear, nonlinear):
diff --git a/pyomo/repn/plugins/gams_writer.py b/pyomo/repn/plugins/gams_writer.py
index 3da385fb7aa..5d76b63e2af 100644
--- a/pyomo/repn/plugins/gams_writer.py
+++ b/pyomo/repn/plugins/gams_writer.py
@@ -205,7 +205,7 @@ def expression_to_string(expr, treechecker, smap=None, output_fixed_variables=Fa
     return expr_str, visitor.is_discontinuous
 
 
-class Categorizer(object):
+class Categorizer:
     """Class for representing categorized variables.
 
     Given a list of variable names and a symbol map, categorizes the variable
@@ -252,7 +252,7 @@ def __iter__(self):
                 yield category, var_name
 
 
-class StorageTreeChecker(object):
+class StorageTreeChecker:
     def __init__(self, model):
         # blocks are hashable so we can use a normal set
         self.tree = {model}
diff --git a/pyomo/repn/plugins/lp_writer.py b/pyomo/repn/plugins/lp_writer.py
index 1bfbbd6a2be..5e6360f0289 100644
--- a/pyomo/repn/plugins/lp_writer.py
+++ b/pyomo/repn/plugins/lp_writer.py
@@ -61,7 +61,7 @@
 
 
 # TODO: make a proper base class
-class LPWriterInfo(object):
+class LPWriterInfo:
     """Return type for LPWriter.write()
 
     Attributes
@@ -81,7 +81,7 @@ def __init__(self, symbol_map):
     'cpxlp_v2', 'Generate the corresponding CPLEX LP file (version 2).'
 )
 @WriterFactory.register('lp_v2', 'Generate the corresponding LP file (version 2).')
-class LPWriter(object):
+class LPWriter:
     CONFIG = ConfigBlock('lpwriter')
     CONFIG.declare(
         'show_section_timing',
@@ -242,7 +242,7 @@ def write(self, model, ostream, **options):
             return _LPWriter_impl(ostream, config).write(model)
 
 
-class _LPWriter_impl(object):
+class _LPWriter_impl:
     def __init__(self, ostream, config):
         self.ostream = ostream
         self.config = config
diff --git a/pyomo/repn/plugins/nl_writer.py b/pyomo/repn/plugins/nl_writer.py
index f009f76c3d0..a96f29e0f18 100644
--- a/pyomo/repn/plugins/nl_writer.py
+++ b/pyomo/repn/plugins/nl_writer.py
@@ -86,7 +86,7 @@
 
 
 # TODO: make a proper base class
-class NLWriterInfo(object):
+class NLWriterInfo:
     """Return type for NLWriter.write()
 
     Attributes
@@ -163,7 +163,7 @@ def __init__(
 
 
 @WriterFactory.register('nl_v2', 'Generate the corresponding AMPL NL file (version 2).')
-class NLWriter(object):
+class NLWriter:
     CONFIG = ConfigDict('nlwriter')
     CONFIG.declare(
         'show_section_timing',
@@ -389,7 +389,7 @@ def _generate_symbol_map(self, info):
         return symbol_map
 
 
-class _SuffixData(object):
+class _SuffixData:
     def __init__(self, name):
         self.name = name
         self.obj = {}
@@ -492,14 +492,14 @@ def __call__(self, obj):
         return ans
 
 
-class _NoScalingFactor(object):
+class _NoScalingFactor:
     scale = False
 
     def __call__(self, obj):
         return 1
 
 
-class _NLWriter_impl(object):
+class _NLWriter_impl:
     def __init__(self, ostream, rowstream, colstream, config):
         self.ostream = ostream
         self.rowstream = rowstream
diff --git a/pyomo/repn/plugins/parameterized_standard_form.py b/pyomo/repn/plugins/parameterized_standard_form.py
index 94474172b16..31b41e1b73c 100644
--- a/pyomo/repn/plugins/parameterized_standard_form.py
+++ b/pyomo/repn/plugins/parameterized_standard_form.py
@@ -95,7 +95,7 @@ def write(self, model, ostream=None, **options):
             return _ParameterizedLinearStandardFormCompiler_impl(config).write(model)
 
 
-class _SparseMatrixBase(object):
+class _SparseMatrixBase:
     def __init__(self, matrix_data, shape):
         (data, indices, indptr) = matrix_data
         (nrows, ncols) = shape
diff --git a/pyomo/repn/plugins/standard_form.py b/pyomo/repn/plugins/standard_form.py
index 89fac2d2006..32e1c8a4410 100644
--- a/pyomo/repn/plugins/standard_form.py
+++ b/pyomo/repn/plugins/standard_form.py
@@ -60,7 +60,7 @@
 
 
 # TODO: make a proper base class
-class LinearStandardFormInfo(object):
+class LinearStandardFormInfo:
     """Return type for LinearStandardFormCompiler.write()
 
     Attributes
@@ -138,7 +138,7 @@ def b(self):
     'compile_standard_form',
     r'Compile an LP to standard form (:math:`\min c^Tx s.t. Ax \le b)`',
 )
-class LinearStandardFormCompiler(object):
+class LinearStandardFormCompiler:
     r"""Compiler to convert an LP to the matrix representation of the
     standard form:
 
@@ -268,7 +268,7 @@ def write(self, model, ostream=None, **options):
             return _LinearStandardFormCompiler_impl(config).write(model)
 
 
-class _LinearStandardFormCompiler_impl(object):
+class _LinearStandardFormCompiler_impl:
     # Making these methods class attributes so that others can change the hooks
     _get_visitor = LinearRepnVisitor
     _to_vector = None
diff --git a/pyomo/repn/quadratic.py b/pyomo/repn/quadratic.py
index e9a9269066f..05904db1328 100644
--- a/pyomo/repn/quadratic.py
+++ b/pyomo/repn/quadratic.py
@@ -39,7 +39,7 @@
 _QUADRATIC = linear.ExprType.QUADRATIC
 
 
-class QuadraticRepn(object):
+class QuadraticRepn:
     __slots__ = ("multiplier", "constant", "linear", "quadratic", "nonlinear")
 
     def __init__(self):
diff --git a/pyomo/repn/standard_repn.py b/pyomo/repn/standard_repn.py
index 3f7abfde8e8..3d541c5eb33 100644
--- a/pyomo/repn/standard_repn.py
+++ b/pyomo/repn/standard_repn.py
@@ -51,7 +51,7 @@ def isclose_const(a, b, rel_tol=1e-9, abs_tol=0.0):
     return abs(a - b) <= max(rel_tol * max(abs(a), abs(b)), abs_tol)
 
 
-class StandardRepn(object):
+class StandardRepn:
     """
     This class defines a standard/common representation for Pyomo expressions
     that provides an efficient interface for writing all models.
@@ -421,7 +421,7 @@ def generate_standard_repn(
 ##-----------------------------------------------------------------------
 
 
-class ResultsWithQuadratics(object):
+class ResultsWithQuadratics:
     __slot__ = ('const', 'nonl', 'linear', 'quadratic')
 
     def __init__(self, constant=0, nonl=0, linear=None, quadratic=None):
@@ -447,7 +447,7 @@ def __str__(self):  # pragma: nocover
         )
 
 
-class ResultsWithoutQuadratics(object):
+class ResultsWithoutQuadratics:
     __slot__ = ('const', 'nonl', 'linear')
 
     def __init__(self, constant=0, nonl=0, linear=None):
diff --git a/pyomo/repn/tests/ampl/test_ampl_nl.py b/pyomo/repn/tests/ampl/test_ampl_nl.py
index 4c680cd6c15..0f396e96d40 100644
--- a/pyomo/repn/tests/ampl/test_ampl_nl.py
+++ b/pyomo/repn/tests/ampl/test_ampl_nl.py
@@ -37,7 +37,7 @@
 thisdir = this_file_dir()
 
 
-class _NLWriter_suite(object):
+class _NLWriter_suite:
     @classmethod
     def setUpClass(cls):
         cls.context = TempfileManager.new_context()
diff --git a/pyomo/repn/tests/ampl/test_nlv2.py b/pyomo/repn/tests/ampl/test_nlv2.py
index 932615be119..3624cc45a55 100644
--- a/pyomo/repn/tests/ampl/test_nlv2.py
+++ b/pyomo/repn/tests/ampl/test_nlv2.py
@@ -51,7 +51,7 @@
 nan = float('nan')
 
 
-class INFO(object):
+class INFO:
     def __init__(self, symbolic=False):
         self.subexpression_cache = {}
         self.external_functions = {}
diff --git a/pyomo/repn/tests/ampl/test_suffixes.py b/pyomo/repn/tests/ampl/test_suffixes.py
index 9e6d395ebfb..8822c55b0da 100644
--- a/pyomo/repn/tests/ampl/test_suffixes.py
+++ b/pyomo/repn/tests/ampl/test_suffixes.py
@@ -34,7 +34,7 @@
 currdir = this_file_dir()
 
 
-class SuffixTester(object):
+class SuffixTester:
     @classmethod
     def setUpClass(cls):
         cls.context = TempfileManager.new_context()
diff --git a/pyomo/repn/tests/baron/test_baron.py b/pyomo/repn/tests/baron/test_baron.py
index a11c0c528a1..309f09a5a37 100644
--- a/pyomo/repn/tests/baron/test_baron.py
+++ b/pyomo/repn/tests/baron/test_baron.py
@@ -275,7 +275,7 @@ def test_issue_2819(self):
 
 
 # class TestBaron_writer(unittest.TestCase):
-class XTestBaron_writer(object):
+class XTestBaron_writer:
     """These tests verified that the BARON writer complained loudly for
     variables that were not on the model, not on an active block, or not
     on a Block ctype.  As we are relaxing that requirement throughout
diff --git a/pyomo/repn/tests/cpxlp/test_cpxlp.py b/pyomo/repn/tests/cpxlp/test_cpxlp.py
index 0d66e750823..a2340bfc124 100644
--- a/pyomo/repn/tests/cpxlp/test_cpxlp.py
+++ b/pyomo/repn/tests/cpxlp/test_cpxlp.py
@@ -27,7 +27,7 @@
 thisdir = this_file_dir()
 
 
-class _CPXLPOrdering_Suite(object):
+class _CPXLPOrdering_Suite:
     @classmethod
     def setUpClass(cls):
         cls.context = TempfileManager.new_context()
diff --git a/pyomo/repn/tests/test_plugins.py b/pyomo/repn/tests/test_plugins.py
index 76805630f5c..8b2a2ca743a 100644
--- a/pyomo/repn/tests/test_plugins.py
+++ b/pyomo/repn/tests/test_plugins.py
@@ -26,7 +26,7 @@ def test_active(self):
             WriterFactory.get_class('lp'), WriterFactory.get_class(f'lp_v{ver}')
         )
 
-        class TMP(object):
+        class TMP:
             pass
 
         WriterFactory.register('test_writer')(TMP)
diff --git a/pyomo/repn/tests/test_standard.py b/pyomo/repn/tests/test_standard.py
index c1912b463e1..21f77caa087 100644
--- a/pyomo/repn/tests/test_standard.py
+++ b/pyomo/repn/tests/test_standard.py
@@ -4418,7 +4418,7 @@ class Etype(pyomo.kernel.expression):
         self.assertEqual(str(rep.to_expression()), "(1 + <vtype>)*<vtype>")
 
     def test_error1(self):
-        class Foo(object):
+        class Foo:
             pass
 
         e = Foo()
diff --git a/pyomo/repn/tests/test_util.py b/pyomo/repn/tests/test_util.py
index 724e52e2899..6554089294c 100644
--- a/pyomo/repn/tests/test_util.py
+++ b/pyomo/repn/tests/test_util.py
@@ -254,7 +254,7 @@ def test_apply_operation(self):
             pyomo.repn.util.HALT_ON_EVALUATION_ERROR = _halt
 
     def test_complex_number_error(self):
-        class Visitor(object):
+        class Visitor:
             pass
 
         visitor = Visitor()
@@ -392,7 +392,7 @@ def test_FileDeterminism_to_SortComponents(self):
         )
 
     def test_initialize_var_map_from_column_order(self):
-        class MockConfig(object):
+        class MockConfig:
             column_order = None
             file_determinism = FileDeterminism(0)
 
@@ -520,7 +520,7 @@ class MockConfig(object):
         self.assertEqual(MockConfig.column_order, ref)
 
     def test_ordered_active_constraints(self):
-        class MockConfig(object):
+        class MockConfig:
             row_order = None
             file_determinism = FileDeterminism(0)
 
@@ -737,7 +737,7 @@ def _before_var(visitor, child):
             def _before_named_expression(visitor, child):
                 return child
 
-        class VisitorTester(object):
+        class VisitorTester:
             def check_constant(self, value, node):
                 return value
 
diff --git a/pyomo/repn/util.py b/pyomo/repn/util.py
index 4a51f87fc78..cf5e5aaeb0d 100644
--- a/pyomo/repn/util.py
+++ b/pyomo/repn/util.py
@@ -758,7 +758,7 @@ def ordered_active_constraints(model, config):
     return sorted(constraints, key=lambda x: _row_getter(id(x), _n))
 
 
-class VarRecorder(object):
+class VarRecorder:
     def __init__(self, var_map, sorter):
         self.var_map = var_map
         self.sorter = sorter
@@ -781,7 +781,7 @@ def add(self, var):
                 vm[id(v)] = v
 
 
-class OrderedVarRecorder(object):
+class OrderedVarRecorder:
     def __init__(self, var_map, var_order, sorter):
         self.var_map = var_map
         self.var_order = var_order
@@ -808,7 +808,7 @@ def add(self, var):
                 vm[vid] = v
 
 
-class TemplateVarRecorder(object):
+class TemplateVarRecorder:
     def __init__(self, var_map, var_order, sorter):
         self.var_map = var_map
         self._var_order = var_order
diff --git a/pyomo/scripting/plugins/build_ext.py b/pyomo/scripting/plugins/build_ext.py
index cdf70a3254b..028531ed9ad 100644
--- a/pyomo/scripting/plugins/build_ext.py
+++ b/pyomo/scripting/plugins/build_ext.py
@@ -16,7 +16,7 @@
 from pyomo.scripting.pyomo_parser import add_subparser
 
 
-class ExtensionBuilder(object):
+class ExtensionBuilder:
     def create_parser(self, parser):
         return parser
 
diff --git a/pyomo/scripting/plugins/download.py b/pyomo/scripting/plugins/download.py
index 80d5d643fa3..f3afc546dee 100644
--- a/pyomo/scripting/plugins/download.py
+++ b/pyomo/scripting/plugins/download.py
@@ -15,7 +15,7 @@
 from pyomo.scripting.pyomo_parser import add_subparser
 
 
-class GroupDownloader(object):
+class GroupDownloader:
     def __init__(self):
         self.downloader = FileDownloader()
 
diff --git a/pyomo/scripting/solve_config.py b/pyomo/scripting/solve_config.py
index 35f0fbb8dbf..69831a3c6c8 100644
--- a/pyomo/scripting/solve_config.py
+++ b/pyomo/scripting/solve_config.py
@@ -12,7 +12,7 @@
 from pyomo.common.config import ConfigBlock, ConfigList, ConfigValue
 
 
-class Default_Config(object):
+class Default_Config:
     def config_block(self, init=False):
         config, blocks = minlp_config_block(init=init)
         return config, blocks
diff --git a/pyomo/scripting/util.py b/pyomo/scripting/util.py
index 35b5c090bd5..00f517ef2ad 100644
--- a/pyomo/scripting/util.py
+++ b/pyomo/scripting/util.py
@@ -912,7 +912,7 @@ def configure_loggers(options=None, shutdown=False):
 configure_loggers.fileLogger = None
 
 
-class PyomoCommandLogContext(object):
+class PyomoCommandLogContext:
     """Context manager to setup/restore logging for the Pyomo command"""
 
     def __init__(self, options):
diff --git a/pyomo/solvers/mockmip.py b/pyomo/solvers/mockmip.py
index 626c289baf3..1a00c833a0d 100644
--- a/pyomo/solvers/mockmip.py
+++ b/pyomo/solvers/mockmip.py
@@ -17,7 +17,7 @@
 from pyomo.opt.base.solvers import _extract_version
 
 
-class MockMIP(object):
+class MockMIP:
     """Methods used to create a mock MIP solver used for testing"""
 
     def __init__(self, mockdir):
diff --git a/pyomo/solvers/plugins/converter/ampl.py b/pyomo/solvers/plugins/converter/ampl.py
index 69a0eea382f..b2338917b5d 100644
--- a/pyomo/solvers/plugins/converter/ampl.py
+++ b/pyomo/solvers/plugins/converter/ampl.py
@@ -20,7 +20,7 @@
 
 
 @ProblemConverterFactory.register('ampl')
-class AmplMIPConverter(object):
+class AmplMIPConverter:
     def can_convert(self, from_type, to_type):
         """Returns true if this object supports the specified conversion"""
         #
diff --git a/pyomo/solvers/plugins/converter/glpsol.py b/pyomo/solvers/plugins/converter/glpsol.py
index b0da85e0e13..33792d5ed1d 100644
--- a/pyomo/solvers/plugins/converter/glpsol.py
+++ b/pyomo/solvers/plugins/converter/glpsol.py
@@ -20,7 +20,7 @@
 
 
 @ProblemConverterFactory.register('glpsol')
-class GlpsolMIPConverter(object):
+class GlpsolMIPConverter:
     def can_convert(self, from_type, to_type):
         """Returns true if this object supports the specified conversion"""
         #
diff --git a/pyomo/solvers/plugins/converter/model.py b/pyomo/solvers/plugins/converter/model.py
index d06c9dd2a3b..40c1003cda6 100644
--- a/pyomo/solvers/plugins/converter/model.py
+++ b/pyomo/solvers/plugins/converter/model.py
@@ -20,7 +20,7 @@
 
 
 @ProblemConverterFactory.register('pyomo')
-class PyomoMIPConverter(object):
+class PyomoMIPConverter:
     pico_converter = PicoMIPConverter()
 
     def can_convert(self, from_type, to_type):
diff --git a/pyomo/solvers/plugins/converter/pico.py b/pyomo/solvers/plugins/converter/pico.py
index bb5a8955693..74c500dcd41 100644
--- a/pyomo/solvers/plugins/converter/pico.py
+++ b/pyomo/solvers/plugins/converter/pico.py
@@ -19,7 +19,7 @@
 from pyomo.opt.base import ProblemFormat, ConverterError
 
 
-class PicoMIPConverter(object):
+class PicoMIPConverter:
     def can_convert(self, from_type, to_type):
         """Returns true if this object supports the specified conversion"""
         #
diff --git a/pyomo/solvers/plugins/solvers/CPLEX.py b/pyomo/solvers/plugins/solvers/CPLEX.py
index f684525bac9..7e959899aed 100644
--- a/pyomo/solvers/plugins/solvers/CPLEX.py
+++ b/pyomo/solvers/plugins/solvers/CPLEX.py
@@ -132,7 +132,7 @@ def __new__(cls, *args, **kwds):
         return opt
 
 
-class ORDFileSchema(object):
+class ORDFileSchema:
     HEADER = "* ENCODING=ISO-8859-1\nNAME             Priority Order\n"
     FOOTER = "ENDATA\n"
 
diff --git a/pyomo/solvers/plugins/solvers/GAMS.py b/pyomo/solvers/plugins/solvers/GAMS.py
index 40c40921d72..ece8bc5a37c 100644
--- a/pyomo/solvers/plugins/solvers/GAMS.py
+++ b/pyomo/solvers/plugins/solvers/GAMS.py
@@ -46,7 +46,7 @@
 logger = logging.getLogger('pyomo.solvers')
 
 
-class _GAMSSolver(object):
+class _GAMSSolver:
     """Aggregate of common methods for GAMS interfaces"""
 
     def __init__(self, **kwds):
diff --git a/pyomo/solvers/plugins/solvers/cplex_direct.py b/pyomo/solvers/plugins/solvers/cplex_direct.py
index 31ad292676c..61615265fb6 100644
--- a/pyomo/solvers/plugins/solvers/cplex_direct.py
+++ b/pyomo/solvers/plugins/solvers/cplex_direct.py
@@ -39,7 +39,7 @@ class DegreeError(ValueError):
     pass
 
 
-class _CplexExpr(object):
+class _CplexExpr:
     def __init__(
         self,
         variables,
@@ -65,7 +65,7 @@ def _is_numeric(x):
     return True
 
 
-class _VariableData(object):
+class _VariableData:
     def __init__(self, solver_model):
         self._solver_model = solver_model
         self.lb = []
@@ -85,7 +85,7 @@ def store_in_cplex(self):
         )
 
 
-class _LinearConstraintData(object):
+class _LinearConstraintData:
     def __init__(self, solver_model):
         self._solver_model = solver_model
         self.lin_expr = []
diff --git a/pyomo/solvers/plugins/solvers/xpress_direct.py b/pyomo/solvers/plugins/solvers/xpress_direct.py
index a3ae6cc5800..f1c5919b0e1 100644
--- a/pyomo/solvers/plugins/solvers/xpress_direct.py
+++ b/pyomo/solvers/plugins/solvers/xpress_direct.py
@@ -170,7 +170,7 @@ def _addConstraint(
         ComponentMap.hasher.hashable(xpress.var, False)
 
 
-class _xpress_importer_class(object):
+class _xpress_importer_class:
     # We want to be able to *update* the message that the deferred
     # import generates using the stdout recorded during the actual
     # import.  As strings are immutable in Python, we will give this
diff --git a/pyomo/solvers/tests/checks/test_cplex.py b/pyomo/solvers/tests/checks/test_cplex.py
index 1e06812f7d3..86eccc97263 100644
--- a/pyomo/solvers/tests/checks/test_cplex.py
+++ b/pyomo/solvers/tests/checks/test_cplex.py
@@ -35,12 +35,12 @@
 )
 
 
-class _mock_cplex_128(object):
+class _mock_cplex_128:
     def version(self):
         return (12, 8, 0)
 
 
-class _mock_cplex_126(object):
+class _mock_cplex_126:
     def version(self):
         return (12, 6, 0)
 
diff --git a/pyomo/solvers/tests/checks/test_xpress_persistent.py b/pyomo/solvers/tests/checks/test_xpress_persistent.py
index ad066af20e0..d5ec3a78d4a 100644
--- a/pyomo/solvers/tests/checks/test_xpress_persistent.py
+++ b/pyomo/solvers/tests/checks/test_xpress_persistent.py
@@ -375,7 +375,7 @@ def test_nonconvexqp_infeasible(self):
         )
 
     def test_available(self):
-        class mock_xpress(object):
+        class mock_xpress:
             def __init__(self, importable, initable):
                 self._initable = initable
                 xpd.xpress_available = importable
diff --git a/pyomo/solvers/tests/mip/test_convert.py b/pyomo/solvers/tests/mip/test_convert.py
index 07529223037..e368bbad6f6 100644
--- a/pyomo/solvers/tests/mip/test_convert.py
+++ b/pyomo/solvers/tests/mip/test_convert.py
@@ -37,7 +37,7 @@ def filter(line):
 deleteFiles = True
 
 
-class MockArg(object):
+class MockArg:
     def __init__(self):
         pass
 
diff --git a/pyomo/solvers/tests/models/base.py b/pyomo/solvers/tests/models/base.py
index 020ae0a044e..4f130da0c8d 100644
--- a/pyomo/solvers/tests/models/base.py
+++ b/pyomo/solvers/tests/models/base.py
@@ -43,7 +43,7 @@ def register_model(cls):
     return cls
 
 
-class _BaseTestModel(object):
+class _BaseTestModel:
     """
     This is a base class for test models
     """
diff --git a/pyomo/solvers/wrappers.py b/pyomo/solvers/wrappers.py
index b8c4dba08e3..eca20d8ab7d 100644
--- a/pyomo/solvers/wrappers.py
+++ b/pyomo/solvers/wrappers.py
@@ -10,6 +10,6 @@
 #  ___________________________________________________________________________
 
 
-class MIPSolverWrapper(object):
+class MIPSolverWrapper:
     def add(self, constraint):  # pragma:nocover
         pass
diff --git a/pyomo/util/subsystems.py b/pyomo/util/subsystems.py
index 20e2c23fc4d..5b3e9666fa7 100644
--- a/pyomo/util/subsystems.py
+++ b/pyomo/util/subsystems.py
@@ -164,7 +164,7 @@ def generate_subsystem_blocks(subsystems, include_fixed=False):
         yield block, list(block.input_vars.values())
 
 
-class TemporarySubsystemManager(object):
+class TemporarySubsystemManager:
     """This class is a context manager for cases when we want to
     temporarily fix or deactivate certain variables or constraints
     in order to perform some solve or calculation with the resulting
diff --git a/scripts/performance/compare.py b/scripts/performance/compare.py
index 5ee19dd63d3..e42c46be823 100755
--- a/scripts/performance/compare.py
+++ b/scripts/performance/compare.py
@@ -31,7 +31,7 @@
 #      stdev(x)**2 / card(x)  +  stdev(y)**2 / card(y) )
 
 
-class Result(object):
+class Result:
     z_threshold = 1.6448536269514722  # 95%
     # z_threshold = 1.2815515655446004  # 90%
     # z_threshold = 0.8416212335729143  # 80%
diff --git a/scripts/performance/main.py b/scripts/performance/main.py
index 3adc956d925..b8ec14aebe9 100755
--- a/scripts/performance/main.py
+++ b/scripts/performance/main.py
@@ -75,7 +75,7 @@ def emit(self, record):
             cat_data[name] = val
 
 
-class DataRecorder(object):
+class DataRecorder:
     """pytest plugin to add a 'testdata' attribute to all tests
 
     This plugin adds an OrderedDict `testdata` attribute to all tests,
diff --git a/setup.py b/setup.py
index 043b0a637f2..ff5c9274df9 100644
--- a/setup.py
+++ b/setup.py
@@ -173,7 +173,7 @@ def run(self):
         print(' '.join(deps))
 
     def _print_deps(self, deplist):
-        class version_cmp(object):
+        class version_cmp:
             ver = tuple(map(int, platform.python_version_tuple()[:2]))
 
             def __lt__(self, other):