This release drops support for PHP 7.4 and PHP 8.0, increasing the minimum required version to PHP 8.1 (if you're still on an older version of PHP, then Composer will keep you on an 1.0.x version until you upgrade). This matches the officially supported versions and is also a requirement by both PHPBench (which is now used by the library to enable performance benchmarking) and PHPUnit 10.
With the addition of PHPBench, there were also some internal changes made to slightly improve the performance of the library (measured on PHP 8.1.27 and PHP 8.3.10).