Magento Commerce and Magento Open Source 2.3.3, 2.2.10 bring changes to supported versions of PHP.
PHP Support in Magento 2.2.x
Until now, 2.2.0-2.2.9 versions supported PHP versions up to 7.1. With security support for PHP 7.1 ending on December 1, 2019 and because Magento 2.2 is supported until the end of 2019, we are introducing support for PHP 7.2 in the release of Magento Commerce and Magento Open Source 2.2.10.
For compliance reasons, merchants are encouraged to consider upgrading their systems to PHP 7.2. Note, it is possible that some extensions and customizations might not be compatible with PHP 7.2. Make sure to thoroughly test and evaluate your store before running a live site on PHP 7.2.
Please note that PHP 7.0 reached End of Life on January 1, 2019. While Magento 2.2.10 will install on PHP 7.0, we have not tested it and no fixes will be released for it. We recommend updating to a supported version of PHP.
PHP Support in Magento 2.3.x
While 2.3.x versions already support PHP 7.2, Magento 2.3.3 brings with it support for PHP 7.3, as the Magento 2.3.x series will continue to receive software support later than the end of life for PHP 7.2 support (coming on November 30, 2020).
This allows new projects to start using PHP 7.3 and existing stores to gradually start supporting PHP 7.3. Magento Marketplace extension vendors should make sure that their extensions are compatible with PHP 7.3 when publishing a new version.