Symfony 8.0

Symfony 8.0 is a major-version line. It raises the minimum PHP requirement to PHP 8.4 and removes APIs and compatibility layers that had been deprecated in the Symfony 7 generation. Applications and bundles that still use those deprecated contracts, configuration forms, method signatures, or extension points must be changed rather than relying on backward-compatible behaviour. The upgrade therefore includes both a PHP platform upgrade and a code and dependency compatibility review.

Symfony 8.0 has reached end of life, so it no longer receives vendor security fixes, bug fixes, or compatibility maintenance. A newly discovered issue in a Symfony component used by the application may require a local workaround or an unsupported patch. Remaining on this line also increases dependency risk: maintained bundles, tooling, and PHP libraries can move their supported Symfony and PHP ranges forward, making routine upgrades harder and turning a later migration into a larger combined change.

Choose a currently supported Symfony target and confirm its PHP requirement before changing application dependencies. Upgrade the runtime and CI environments to the required PHP version, then update Composer constraints for Symfony and all Symfony components together. Run Composer's dependency checks to identify bundles that block the target version, replacing or upgrading unsupported packages where necessary. Before the major upgrade, eliminate deprecation notices from the existing application and test suite; then address removed APIs, changed type requirements, and configuration changes reported during the upgrade. Validate the result with the full automated test suite, production-like smoke tests, and checks for framework-dependent integrations such as queues, caches, sessions, authentication, mail, and deployment tooling.