PHP 7.4 was released in November 2019 with several new features including typed properties, arrow functions, null coalescing assignment, spread operator for arrays, and performance improvements. It allows covariance and contravariance for parameter and return types. New features also include weak references, preloading to improve performance, and deprecation of left-associative ternary operators. Benchmark tests showed PHP 7.4 was up to 26% faster than earlier versions.