diff --git a/CHANGELOG.md b/CHANGELOG.md
index c9f67c32..a261e52b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # CHANGELOG
 
+## v0.12.3 - 1 December 2025
+
+- Converts `PosixPath` objects to `str` before passing to pytest's `args` during custom unit and
+  regression test collection.
+- Pins the maximum version of Jupyter-Book to be "<2" until the documentation has been migrated.
+
 ## v0.12.2 - 16 October 2025
 
 - Reinstate the ability to have extra columns in the weather profile to avoid upstream conflicts,
diff --git a/pyproject.toml b/pyproject.toml
index 8d5e778a..0ac8d52b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -75,7 +75,7 @@ dev = [
     "pyupgrade",
 ]
 docs = [
-    "jupyter-book>=0.15",
+    "jupyter-book>=1,<2",
     "myst-nb>=0.16",
     "myst-parser>=0.17",
     "linkify-it-py>=2",
diff --git a/tests/conftest.py b/tests/conftest.py
index 6a1d3c1f..f994504d 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -34,10 +34,12 @@ def pytest_configure(config):  # noqa: D103
     regression = config.getoption("--regression")
 
     # Provide the appropriate directories
-    unit_tests = [el for el in (ROOT / "unit").iterdir() if el.suffix == ".py"]
+    unit_tests = [str(el) for el in (ROOT / "unit").iterdir() if el.suffix == ".py"]
     regression_tests = [
-        el for el in (ROOT / "regression").iterdir() if el.suffix == ".py"
+        str(el) for el in (ROOT / "regression").iterdir() if el.suffix == ".py"
     ]
+    unit_tests.sort()
+    regression_tests.sort()
 
     # If both, run them all; if neither skip any modifications; otherwise run just the
     # appropriate subset
diff --git a/wombat/__init__.py b/wombat/__init__.py
index 5e8b8fbf..e6f0d073 100644
--- a/wombat/__init__.py
+++ b/wombat/__init__.py
@@ -4,4 +4,4 @@
 from wombat.core.library import create_library_structure, load_yaml
 
 
-__version__ = "0.12.2"
+__version__ = "0.12.3"