diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index e570994b..edd1ddbe 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -13,7 +13,7 @@ jobs:
   look-for-outdated-code:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Install dependencies
         run: |
           sudo apt update && sudo apt install python3-pip
diff --git a/pyproject.toml b/pyproject.toml
index 26e6e6c7..a3292799 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -31,7 +31,7 @@ markers = ["reconcile", "conflict", "migrate", "discourse"]
 # Formatting tools configuration
 [tool.black]
 line-length = 99
-target-version = ["py310"]
+target-version = ["py312"]
 
 [tool.isort]
 line_length = 99
diff --git a/src/gatekeeper/__init__.py b/src/gatekeeper/__init__.py
index 99c4a147..69f421a3 100644
--- a/src/gatekeeper/__init__.py
+++ b/src/gatekeeper/__init__.py
@@ -2,6 +2,7 @@
 # See LICENSE file for licensing details.
 
 """Library for uploading docs to charmhub."""
+
 import logging
 from collections.abc import Iterable, Iterator
 from itertools import tee
diff --git a/src/gatekeeper/constants.py b/src/gatekeeper/constants.py
index 27eb6b4c..90f52dfb 100644
--- a/src/gatekeeper/constants.py
+++ b/src/gatekeeper/constants.py
@@ -6,6 +6,7 @@
 The use of this module should be limited to cases where the constant is not better placed in
 another module or to resolve circular imports.
 """
+
 DEFAULT_BRANCH = "main"
 DOCUMENTATION_TAG = "discourse-gatekeeper/base-content"
 
diff --git a/src/gatekeeper/docs_directory.py b/src/gatekeeper/docs_directory.py
index 638d0c17..29ffbaaf 100644
--- a/src/gatekeeper/docs_directory.py
+++ b/src/gatekeeper/docs_directory.py
@@ -2,6 +2,7 @@
 # See LICENSE file for licensing details.
 
 """Class for reading the docs directory."""
+
 import itertools
 import typing
 from functools import partial
diff --git a/tests/conftest.py b/tests/conftest.py
index 565c553a..e25f20d3 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -69,6 +69,11 @@ def fixture_git_repo(
     """Create repository with mocked upstream."""
     repo = Repo.clone_from(url=upstream_git_repo.working_dir, to_path=repository_path)
 
+    # Disable GPG signing for tags in test environment
+    writer = repo.config_writer()
+    writer.set_value("tag", "gpgSign", "false")
+    writer.release()
+
     repo.git.checkout("-b", default_branch)
 
     # Go into detached head mode to reflect how GitHub performs the checkout
@@ -98,6 +103,8 @@ def fixture_upstream_git_repo(upstream_repository_path: Path, default_branch: st
     writer = upstream_repository.config_writer()
     writer.set_value("user", "name", "upstream_user")
     writer.set_value("user", "email", "upstream_email")
+    # Disable GPG signing for tags in test environment
+    writer.set_value("tag", "gpgSign", "false")
     writer.release()
 
     upstream_repository.git.checkout("-b", default_branch)
@@ -106,6 +113,7 @@ def fixture_upstream_git_repo(upstream_repository_path: Path, default_branch: st
     upstream_repository.git.commit("-m", "'initial commit'")
 
     upstream_repository.git.checkout("-b", BASE_REMOTE_BRANCH)
+    # Create lightweight tag
     upstream_repository.git.tag(DOCUMENTATION_TAG)
 
     return upstream_repository
diff --git a/tests/integration/conftest.py b/tests/integration/conftest.py
index c12e5dc9..68a413aa 100644
--- a/tests/integration/conftest.py
+++ b/tests/integration/conftest.py
@@ -56,7 +56,9 @@ async def discourse(model: Model) -> Application:
         apps=[postgres_charm_name, redis_charm_name], status="active", raise_on_error=False
     )
 
-    discourse_app: Application = await model.deploy(discourse_charm_name, channel="edge")
+    discourse_app: Application = await model.deploy(
+        discourse_charm_name, channel="edge", revision=229
+    )
     await model.wait_for_idle(apps=[discourse_charm_name], status="waiting", raise_on_error=False)
 
     await model.integrate(discourse_charm_name, f"{postgres_charm_name}:database")
@@ -344,12 +346,12 @@ def discourse_enable_tags(
     headers = {
         "Api-Key": discourse_admin_api_credentials.key,
         "Api-Username": discourse_admin_api_credentials.username,
+        "Content-Type": "application/json",
     }
-    data = {"tagging_enabled": "true"}
     response = requests.put(
-        f"{discourse_address}/admin/site_settings/tagging_enabled",
+        f"{discourse_address}/admin/site_settings/tagging_enabled.json",
         headers=headers,
-        data=data,
+        json={"tagging_enabled": "true"},
         timeout=60,
     )
     assert response.status_code == 200, f"Enabling tagging failed, {response.content=}"
@@ -360,6 +362,10 @@ async def discourse_remove_rate_limits(
     discourse_admin_api_headers: dict[str, str], discourse_address: str
 ):
     """Disables rate limits on discourse."""
+    headers_with_content_type = {
+        **discourse_admin_api_headers,
+        "Content-Type": "application/json",
+    }
     settings = {
         "unique_posts_mins": "0",
         "rate_limit_create_post": "0",
@@ -381,9 +387,9 @@ async def discourse_remove_rate_limits(
     }
     for setting, value in settings.items():
         response = requests.put(
-            f"{discourse_address}/admin/site_settings/{setting}",
-            headers=discourse_admin_api_headers,
-            data={setting: value},
+            f"{discourse_address}/admin/site_settings/{setting}.json",
+            headers=headers_with_content_type,
+            json={setting: value},
             timeout=60,
         )
         assert (
diff --git a/tests/integration/test___init__run_conflict.py b/tests/integration/test___init__run_conflict.py
index d603a296..7591ca1a 100644
--- a/tests/integration/test___init__run_conflict.py
+++ b/tests/integration/test___init__run_conflict.py
@@ -105,7 +105,7 @@ async def test_run_conflict(
     urls_with_actions = reconcile_output.topics
 
     assert len(urls_with_actions) == 2
-    (doc_url, _) = urls_with_actions.keys()
+    doc_url, _ = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (doc_url, index_url)
     doc_table_line_1 = f"| 1 | {doc_table_key} | [{doc_title}]({urlparse(doc_url).path}) |"
     assert_substrings_in_string(
@@ -242,7 +242,7 @@ async def test_run_conflict(
     urls_with_actions = reconcile_output.topics
 
     assert len(urls_with_actions) == 3
-    (alt_doc_url, _, _) = urls_with_actions.keys()
+    alt_doc_url, _, _ = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (alt_doc_url, doc_url, index_url)
     alt_doc_table_line_5 = (
         f"| 1 | {alt_doc_table_key} | [{alt_doc_title}]({urlparse(alt_doc_url).path}) |"
diff --git a/tests/integration/test___init__run_migrate.py b/tests/integration/test___init__run_migrate.py
index acc7eb9b..30f71770 100644
--- a/tests/integration/test___init__run_migrate.py
+++ b/tests/integration/test___init__run_migrate.py
@@ -140,9 +140,7 @@ async def test_run_migrate(
     assert output_migrate.pull_request_url == mock_pull_request.html_url
     assert output_migrate.action == PullRequestAction.OPENED
     assert (upstream_doc_dir / "index.md").is_file()
-    assert (
-        (upstream_doc_dir / "index.md").read_text(encoding="utf-8")
-        == f"""Testing index page.
+    assert (upstream_doc_dir / "index.md").read_text(encoding="utf-8") == f"""Testing index page.
 
 Testing index page content.
 
@@ -160,7 +158,6 @@ async def test_run_migrate(
     1. [Canonical 3](https://canonical.com/projects)
   1. [{content_page_4.content}](group-3/content-4.md)
 1. [Group 5](group-5)"""
-    )
     assert (group_1_path := upstream_doc_dir / "group-1").is_dir()
     assert (group_1_path / migration.GITKEEP_FILENAME).is_file()
     assert (group_2_path := upstream_doc_dir / "group-2").is_dir()
diff --git a/tests/integration/test___init__run_reconcile.py b/tests/integration/test___init__run_reconcile.py
index e28ece4e..8f4125d1 100644
--- a/tests/integration/test___init__run_reconcile.py
+++ b/tests/integration/test___init__run_reconcile.py
@@ -179,7 +179,7 @@ async def test_run(
 
     assert output_reconcile is not None
     assert len(output_reconcile.topics) == 2
-    (doc_url, _) = output_reconcile.topics.keys()
+    doc_url, _ = output_reconcile.topics.keys()
     assert (urls := tuple(output_reconcile.topics)) == (doc_url, index_url)
     doc_table_line_1 = f"| 1 | {doc_table_key} | [{doc_content_1}]({urlparse(doc_url).path}) |"
     assert_substrings_in_string(
@@ -292,7 +292,7 @@ async def test_run(
 
     assert urls_with_actions is not None
     assert len(urls_with_actions) == 3
-    (_, nested_dir_doc_url, _) = urls_with_actions.keys()
+    _, nested_dir_doc_url, _ = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (doc_url, nested_dir_doc_url, index_url)
     nested_dir_doc_table_line_1 = (
         f"| 2 | {nested_dir_doc_table_key} |"
@@ -560,7 +560,7 @@ async def test_run_hidden(
     urls_with_actions = output_reconcile.topics
 
     assert len(urls_with_actions) == 2
-    (doc_url, index_url) = urls_with_actions.keys()
+    doc_url, index_url = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (doc_url, index_url)
     doc_table_line_1 = f"| 1 | {doc_table_key} | [{doc_title}]({urlparse(doc_url).path}) |"
     assert_substrings_in_string(
@@ -673,7 +673,7 @@ async def test_run_hidden(
     urls_with_actions = output_reconcile.topics
 
     assert len(urls_with_actions) == 3
-    (_, alt_doc_url, _) = urls_with_actions.keys()
+    _, alt_doc_url, _ = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (doc_url, alt_doc_url, index_url)
     alt_doc_table_line_4 = (
         f"| | {alt_doc_table_key} | [{alt_doc_title}]({urlparse(alt_doc_url).path}) |"
@@ -795,7 +795,7 @@ async def test_run_external(
     urls_with_actions = output_reconcile.topics
 
     assert len(urls_with_actions) == 2
-    (external_url, index_url) = urls_with_actions.keys()
+    external_url, index_url = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (external_url, index_url)
     item_table_line_1 = f"| 1 | https-canonical-com | [{item_title_1}]({item_url_1}) |"
     assert_substrings_in_string(
@@ -843,7 +843,7 @@ async def test_run_external(
     urls_with_actions = output_reconcile.topics
 
     assert len(urls_with_actions) == 2
-    (external_url, index_url) = urls_with_actions.keys()
+    external_url, index_url = urls_with_actions.keys()
     assert (urls := tuple(urls_with_actions)) == (external_url, index_url)
     item_table_line_3 = f"| 1 | https-canonical-com | [{item_title_3}]({external_url}) |"
     assert_substrings_in_string(
diff --git a/tests/unit/test___init__.py b/tests/unit/test___init__.py
index 3845b346..8616b243 100644
--- a/tests/unit/test___init__.py
+++ b/tests/unit/test___init__.py
@@ -2,6 +2,7 @@
 # See LICENSE file for licensing details.
 # pylint: disable=too-many-lines
 """Unit tests for execution."""
+
 import logging
 from pathlib import Path
 from unittest import mock
@@ -427,7 +428,8 @@ def test__run_reconcile_invalid_external_item(mocked_clients):
     "gatekeeper.repository.Client.metadata",
     types_.Metadata(name="name 1", docs=None),
 )
-def test__run_reconcile_external_item(mocked_clients):
+@mock.patch("requests.head")
+def test__run_reconcile_external_item(mock_requests_head, mocked_clients):
     """
     arrange: given metadata with name but not docs and docs folder with an external item on the
         index
@@ -435,6 +437,11 @@ def test__run_reconcile_external_item(mocked_clients):
     assert: then a documentation page is created and an index page is created with a navigation
         page with the external item.
     """
+    # Mock HTTP HEAD request to avoid network calls
+    mock_response = mock.MagicMock()
+    mock_response.status_code = 200
+    mock_requests_head.return_value = mock_response
+
     mocked_clients.discourse.create_topic.side_effect = [index_url := "url 1"]
 
     with mocked_clients.repository.with_branch(DEFAULT_BRANCH) as repo:
diff --git a/tests/unit/test_check.py b/tests/unit/test_check.py
index 73cb4062..52612992 100644
--- a/tests/unit/test_check.py
+++ b/tests/unit/test_check.py
@@ -5,8 +5,10 @@
 
 import logging
 from typing import NamedTuple, cast
+from unittest import mock
 
 import pytest
+import requests
 
 from gatekeeper import check, types_
 
@@ -492,6 +494,7 @@ def test_external_refs(
     index_contents: tuple[types_.IndexContentsListItem, ...],
     expected_problems: tuple[ExpectedProblem],
     caplog: pytest.LogCaptureFixture,
+    monkeypatch: pytest.MonkeyPatch,
 ):
     """
     arrange: given index_contents
@@ -500,6 +503,38 @@ def test_external_refs(
     """
     caplog.set_level(logging.INFO)
 
+    # Mock requests.head to avoid actual network calls
+    def mock_head(url: str, timeout: int = 60):  # pylint: disable=unused-argument
+        """Mock HEAD request.
+
+        Args:
+            url: The URL to check.
+            timeout: The timeout for the request.
+
+        Returns:
+            A mock response object.
+
+        Raises:
+            ConnectionError: If the URL simulates a connection error.
+        """
+        response = mock.MagicMock(spec=requests.Response)
+
+        # Simulate valid responses for canonical.com URLs
+        if "canonical.com" in url and "invalid" not in url:
+            response.status_code = 200
+        # Simulate 404 for canonica.com (typo) or invalid paths
+        elif "canonica.com" in url or "invalid-page" in url:
+            response.status_code = 404
+        # Simulate connection errors for invalid domains
+        elif "invalid.link.com" in url or "invalid.url.com" in url:
+            raise requests.ConnectionError(f"Connection error for {url}")
+        else:
+            response.status_code = 200
+
+        return response
+
+    monkeypatch.setattr("requests.head", mock_head)
+
     returned_problems = tuple(check.external_refs(index_contents=index_contents))
 
     assert len(returned_problems) == len(expected_problems)
diff --git a/tests/unit/test_discourse.py b/tests/unit/test_discourse.py
index 0f651be4..8c389e06 100644
--- a/tests/unit/test_discourse.py
+++ b/tests/unit/test_discourse.py
@@ -595,22 +595,19 @@ def test_function_discourse_error(
     [
         pytest.param("test content", "test content", id="version 2.6.0 response"),
         pytest.param(
-            textwrap.dedent(
-                """\
+            textwrap.dedent("""\
         test-username | timestamp | # 23
 
         test content
 
         -------------------------
 
-        """
-            ),
+        """),
             "test content",
             id="version 2.8.14 response",
         ),
         pytest.param(
-            textwrap.dedent(
-                """\
+            textwrap.dedent("""\
         test-username | timestamp | # 23
 
         test content
@@ -623,8 +620,7 @@ def test_function_discourse_error(
 
         -------------------------
 
-        """
-            ),
+        """),
             "test content",
             id="version 2.8.14 response with post replies",
         ),
diff --git a/tests/unit/test_index.py b/tests/unit/test_index.py
index f251584e..e5119980 100644
--- a/tests/unit/test_index.py
+++ b/tests/unit/test_index.py
@@ -221,22 +221,16 @@ def _test_get_content_for_server_parameters():
         ),
         # Can't use f-string due to needing new line
         pytest.param(
-            "# contents\n"
-            + (
-                other_content := """#
-line 1"""
-            ),
+            "# contents\n" + (other_content := """#
+line 1"""),
             other_content,
             id="contents followed by header with single line",
         ),
         # Can't use f-string due to needing new line
         pytest.param(
-            "# contents\n"
-            + (
-                other_content := """#
+            "# contents\n" + (other_content := """#
 line 1
-line 2"""
-            ),
+line 2"""),
             other_content,
             id="contents followed by header with multiple lines",
         ),
@@ -250,11 +244,8 @@ def _test_get_content_for_server_parameters():
         ),
         # Can't use f-string due to needing new line
         pytest.param(
-            "# contents\n"
-            + (
-                other_content := """#
-# contents"""
-            ),
+            "# contents\n" + (other_content := """#
+# contents"""),
             other_content,
             id="contents followed by header followed by another contents",
         ),
diff --git a/tox.ini b/tox.ini
index 204fc8e0..cd185038 100644
--- a/tox.ini
+++ b/tox.ini
@@ -12,7 +12,7 @@ tst_path = {toxinidir}/tests/
 all_path = {[vars]src_path} {[vars]main_path} {[vars]tst_path}
 
 [testenv]
-basepython = python3.10
+basepython = python3.12
 allowlist_externals=python
 setenv =
   PYTHONPATH = {toxinidir}:{toxinidir}/lib:{[vars]src_path}
@@ -35,14 +35,13 @@ description = Check code against coding style standards
 deps =
     -r{toxinidir}/requirements.txt
     black
-    flake8<6.0.0
+    flake8
     flake8-docstrings>=1.6
     flake8-copyright>=0.2
     flake8-builtins>=2.0
     flake8-docstrings-complete>=1.0.3
     flake8-test-docs>=1.0
-    ; There is an error with version 6.0.0 related to integers and arguments
-    pyproject-flake8<6.0.0
+    pyproject-flake8
     pep8-naming
     isort
     codespell