4.3.7
Bug-fix release.
Fixed: critical error after plugin, theme, or core updates and rollbacks.
The upgrader_process_complete migration callback was registered under the plugin namespace (Core_Forms\_cf_on_upgrader_complete), but that function is defined in the global namespace, so it was an invalid callback that triggered a fatal TypeError whenever WordPress finished an update or rollback. It surfaced as “There has been a critical error on this website” on the update/rollback screen. The callback is now registered with the correct name, so updates complete cleanly.
PHPStan had originally flagged this; the error had been suppressed in phpstan-baseline.neon rather than fixed. That stale baseline entry is now removed.