WordPress Version
Auto Mail needs a WordPress version equal to or greater than version 5.6 in order to properly work.
PHP Version
Auto Mail requires PHP version 7.2 or higher. We strongly recommend upgrading to PHP 7.4, like WordPress also does.
MySQL Version
Auto Mail requires MySQL version 5.5 or higher. We strongly recommend upgrading to MySQL 5.7 or anything that is currently supported.
Browser Support
Auto Mail follows the same browser version support as WordPress itself. This will generally include current versions, and the last one or two depending on the specific browser, which you can check in the WordPress.org page here.