- Fix numerous compatibility and bug issues across Active Support, Active Record, and adapters (Ruby 3.1, SQLite, PostgreSQL, MySQL) and improve migration handling.
- Add reversible named expression indexes and enable testing of discard/retry behavior on ActiveJob deserialization errors.
- Enhance error messages, plugin Gemfile handling, logger context preservation, and resolve assorted bugs in ActionView, ActionPack, Railties, and plugin generators.