PHP 7 to PHP 8 Migration Checklist

Use this page as a release gate. For explanations, code samples, and breaking-change narratives, follow the deep guide PHP 7 to PHP 8 migration. Official notes start at migration80.

Preflight

• □ Inventory SAPIs (FPM, CLI, cron) and extension lists match across environments
• □ Composer platform.php set to the intended 8.x minor (prefer a supported branch: 8.2–8.5 as of 2026-08-09)
• □ Scan with compatibility checker and deprecated checker
• □ Grep for removed APIs: each(, create_function(, money_format(, get_magic_quotes, old constructors

Code readiness

• □ PHPUnit / integration suite green on PHP 8 in CI
• □ PHPStan/Psalm level raised; @ handlers updated for non-zero error_reporting masks
• □ Null passed into internal non-nullable parameters cleaned (8.1 deprecations)
• □ Dynamic properties inventoried if targeting 8.2+
• □ Named arguments / attributes adopted only after baseline boot succeeds

Runtime & deploy

• □ Docker/base images, Ansible, and panel selectors updated together
• □ OPcache validated; JIT left off unless measured for your workload
• □ Xdebug 3 path maps verified on staging
• □ Rollback image tagged and tested
• □ 24–48h error-rate watch after cutover

Also see 7.4 → 8.x and migration center.