Opt-in occurrence deadlines keep the first timer's exact deadline through false-wake reopens. The original timeout budget stays attached to the logical chain. Conflicting, timed-out or unprovable chains refuse with whole-completion rollback. Legacy chains retain their per-open behavior.
The embedded worker protocol advertises 1.22 and still accepts 1.20 requests. There is no database migration or support-floor change: PHP ^8.2 and Laravel ^12.69.0 or ^13.30.0.
After a workflow has used this policy, roll back to an older Core version only by restoring a pre-upgrade backup. Older normalizers can discard the policy and create a mixed chain; upgrading again does not repair that history.
Verified on Packagist at commit 4e56debcb59546269d8e1a69f31c5e7a111dd7ae. Published-package verification and five Laravel upgrade cells passed, alongside the full source/main qualification in #1067 and #1068.
This publishes Core support. PHP Server advertisement and the SDK release/installed portable qualification remain separate steps tracked in #1066 and sdk-php#269.