PHP Compatibility Checker is a free wordpress plugin to check your wordpress website for compatibility for PHP 7, PHP 5.6, PHP 5.5, PHP 5.4 and PHP 5.3. You can use this plugin on any web host to check PHP version compatibility. This plugin is from WP Engine and it lint your wordpress theme and plugin code and give you a detailed report of compatibility issues. Note that PHP Compatibility Checker cannot detect runtime compatibility issues on your wordpress site. PHP Compatibility Checker uses WP-Cron to scan files in your wordpress website to find issues.