release notes

Author: tdyas

docs/notes/2.26.x.md

@@ -90,6 +90,8 @@ A bug in the Django backend has been fixed so that a repo may have no Django app
 
 [Pytype](https://www.pantsbuild.org/stable/reference/subsystems/pytype) was updated to version 2024.9.13 - which is the [last to support Python 3.8 and Python 3.9](https://github.com/google/pytype/blob/main/CHANGELOG).
 
+The Python backend uses the PyPI `packaging` distribution to parse Python version numbers. In upgrading `packaging` from v21.3 to v24.2, support for parsing "legacy" Python versions was removed. We do not anticipate an issue here (since [PEP 440](https://peps.python.org/pep-0440/) has been around since 2013), but please contact the maintainers if an issue does arise.
+
 #### Shell
 
 The `experiemental_test_shell_command` target type learned several new features: