PHP Versions

PHP versions matter for two reasons: security support and compatibility with your theme/plugins. Performance gains from a version bump are usually incremental compared to OPcache, caching, and database tuning, but staying on a supported version is non-negotiable for a production site.

Quick Summary

• Prefer the latest PHP version that your WordPress stack supports.
• Upgrade via staging first, validate critical flows, then roll out to production.
• Verify required extensions after the upgrade (imagick/gd, curl, mbstring, redis, etc.).

Pick a Target Version

Use these rules to pick a version that stays secure without breaking your stack.

Version Selection Directives

Default: Latest Supported

Choose the newest PHP version that is:

• Supported by your OS/distribution packages (or hosting panel).
• Supported by WordPress core and your critical plugins.

Benefits: ongoing security patches, small runtime improvements, and better long-term maintainability.

Compatibility: One Version Behind

If your stack has a blocker (a payment gateway, a membership plugin, a custom theme), choose the previous still-supported version as an interim step.

This often reduces risk while you plan plugin/theme updates.

Avoid: End-of-Life Versions

Do not run versions that are end-of-life (EOL).

• No security patches.
• Increasing incompatibility with modern plugins.
• Harder incident response when something breaks.

Upgrade Workflow (Safe)

1. Clone to staging: same theme/plugins, similar PHP extensions, copy of the database.
2. Switch PHP version on staging: in your panel or package manager.
3. Smoke-test critical flows:
   • Homepage and a few content templates
   • Login + wp-admin
   • WooCommerce cart/checkout/account (if applicable)
   • Cron jobs / background tasks
4. Check logs: look for fatal errors, warnings, and deprecations.
5. Plan rollback: know how to switch back quickly if needed.
6. Roll to production: during a low-traffic window.

Common Mistakes & Troubleshooting

Configuration Failure	Operational Symptom	Remediation Protocol
Upgrading without staging	Fatal errors or white screens on production.	Upgrade on staging first, update/replace incompatible plugins, then roll out.
Missing extensions after upgrade	Images, HTTP requests, or Redis stop working.	Verify extension packages for the new PHP version (imagick/gd, curl, mbstring, intl, redis, etc.).

What's Next

• OPcache Tuning
• OPcache Preloading
• PHP JIT
• Module Overview