A practical guide to modernizing PHP codebases using PHP 8.x features without requiring full rewrites. Covers Backed Enums for replacing fragile magic strings, readonly properties and classes for enforcing immutability, match expressions to fix switch statement pitfalls, union and intersection types for precise type contracts, named arguments for self-documenting function calls, constructor property promotion to eliminate boilerplate, property hooks (PHP 8.4), the #[Override] attribute (PHP 8.3), new array helpers, and the upcoming pipe operator (PHP 8.5). Also addresses how to use Symfony polyfills to adopt these features on older PHP versions incrementally.