Upgrade your server's PHP to a more current version
Editor Enhancer requires at least PHP 7.x to perform at its best. If you're not running the latest version of PHP, you really should - for many Google-able security reasons. This will be done on your host server through your hosting provider. Most hosts (good hosts) will be able to help you with this, and many provide a dashboard so you can do it yourself. Though, if you're not sure, it's better to ask.