Drupal 9 is end of life as of November 1st, 2023
Drupal 9 relies on several other software projects, including Symfony, CKEditor, and Twig. With Symfony 4's end of life, CKEditor 4's end of life, and Twig 2's end of life all coming up soon, Drupal 9 went end of life on November 1st, 2023. There will be no further releases of Drupal 9.
Two changes for Drupal contributed projects will occur before the end of January 2024. One is that the automated testing platform DrupalCI support for Drupal 9 will stop. The other is that release branches of contributed projects that only support Drupal 9 will be marked unsupported (see the tracking issue for details).
Thanks to everyone who helped create and maintain Drupal 9.
It is time to update to Drupal 10 compatible releases
If you are a site owner
Check the documentation on updating a site to Drupal 10.
If you maintain contributed projects
If a contributed project is not yet compatible with Drupal 10, now is a good time to update it. Check for existing Drupal 10 compatibility issues relevant for your projects.
If your project is already compatible with Drupal 10 but does not yet have a stable release, please tag a release, once you are confident in your project's stability. Where possible, tag a minor release supporting both Drupal 9 and 10 to ensure users have a smooth upgrade path.