This directory provides PHP compatibility functions and polyfills to ensure WordPress runs consistently across different PHP versions. Contains legacy support, function overrides, and version-specific fixes.
compat.php
Core compatibility functions
polyfills/
Modern function emulations
version-check.php
PHP version requirement validation
wpdb-compat.php
Database layer compatibility fixes
deprecated.php
Legacy function deprecation handling
functions.php
Cross-version utility helpers
Legacy compatibility layer required for multi-version PHP support.