diff --git a/pyproject.toml b/pyproject.toml
index bf82322..6746ade 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -73,6 +73,9 @@ ignore_missing_imports = true
 line-length = 100
 
 [tool.ruff.lint]
+# Pin to the default rules from ruff 0.15 and earlier. Ruff 0.16 greatly expanded
+# the default rule set, which reports many issues in the existing code.
+select = ["E4", "E7", "E9", "F"]
 ignore = ["E501"]
 
 [tool.ruff.lint.isort]
diff --git a/requirements-testing.txt b/requirements-testing.txt
index 6634194..1dda313 100644
--- a/requirements-testing.txt
+++ b/requirements-testing.txt
@@ -8,6 +8,6 @@ pytest-asyncio == 1.*
 pytest-cov == 7.*
 pytest-xdist == 3.*
 pywin32 ; sys_platform == 'win32'
-ruff == 0.15.*
+ruff == 0.16.*
 types-pyyaml == 6.*
 twine == 7.*
\ No newline at end of file