PHP maintains several release branches at once. A supported branch initially receives regular bug and security fixes, then moves into a security-only period before reaching end of life. The official schedule is published by the PHP project and changes as newer branches are released.
The lifecycle helps administrators decide whether to upgrade within a branch or migrate to another supported branch. A security-only branch may still receive critical fixes, but it no longer gets the same range of routine maintenance changes as an actively supported branch.
Upstream lifecycle dates do not automatically determine what a Linux distribution or hosting provider supports. A vendor may maintain a separate patched package stream after the PHP project's own branch reaches EOL.
For each application, record its active PHP branch, upstream support phase and vendor-maintenance status. Plan compatibility testing early enough to migrate before the last trusted source of security updates ends.