PHP upgrades and version management for WordPress

PHP upgrades are necessary—and one of the most common sources of WordPress downtime.

Understanding failures

• Why PHP upgrades break WordPress sites
• PHP 8.3 / 8.4 compatibility issues in WordPress (2026 edition)

Version drift and mismatches

• PHP version drift on multi-site servers
• PHP CLI vs PHP-FPM version mismatches

Safer upgrade patterns

• Debugging WordPress after a PHP upgrade
• Safer plugin updates on production WordPress sites

If PHP upgrades feel risky, this section explains why—and how to reduce that risk.