An update can change more than it appears.
The WordPress 6.9 cycle was already in release candidate phase in November 2025. These milestones are designed to verify themes, plugins, and workflows before the final version.
A light protocol is often sufficient.
Testing the homepage, contact form, private area, and content editing in a staging environment covers the essentials. Then, keep a backup and a clear rollback path.
For further reading. WordPress 6.9 Cycle