What is PHP 8 and what major features did it introduce?

PHP 8.0 (released November 2020) introduced significant language improvements. Key features: JIT (Just-In-Time) Compiler for significant performance gains in CPU-intensive code, named arguments (pass arguments by parameter name in any order), attributes (structured metadata for classes, methods, properties — the native replacement for docblock annotations), match expression (strict, exhaustive version of switch), nullsafe operator (?->), constructor property promotion, union types (int|string), throw as an expression, str_contains() / str_starts_with() / str_ends_with() functions, and the Fibers feature (PHP 8.1). PHP 8 fundamentally modernized the language and reduced boilerplate significantly.