In general, we try to follow the PHP Supported Versions dates as closely as possible. PHP 7.4 has been an outlier for this rule in order to allow the WordPress ecosystem some time to catch up; PHP 8.1 will have security support until December 31, 2025.
PHP 7.4 has been maintained on our platform via security backports well past its EOL date of November 28, 2022. We recognize that the removal of PHP 7.4 presents a challenge for customers with sites that rely on older plugins. However, as part of best security practices, WP users should be keeping their software up-to-date (and likewise, plugin developers should be maintaining their plugins).
We have been working with clients to upgrade sites. While this work is ongoing, we will stop allowing new sites on the platform to be created with PHP 7.4 as an option as of Wednesday, 18 September 2024. Existing sites and clones of those sites may still use PHP 7.4 in order to test and assess changes needed to move to PHP 8.1 or higher.