This is a critical oversight in the Slider Revolution 7.1.7 release package. The development team added an execution hook referencing add_ajax_footer_functionality, but they completely forgot to bundle the corresponding method definition inside the RevSliderAdmin class code.Because the hook is actively trying to invoke a static method that does not exist in the code pool, it will trigger an immediate fatal runtime PHP error (or broken backend functionality) when WordPress attempts to compile the admin footer layout.????️ Temporary Patch (Hotfix)Until ThemePunch/Slider Revolution patches this in a version like 7.1.8, you can safely resolve the error using either of the following two quick code fixes.Option A: Safely Define the Missing Method (Recommended)This approach prevents errors and leaves a clean placeholder function ready in case subsequent frontend AJAX dependencies expect it.Open the plugin file: revslider/admin/revslider-admin.class.phpScroll to the very end of the file, right before the closing brace } of the main class.Insert the following dummy method definition:phppublic static function add_ajax_footer_functionality() {
// Temporary stub to prevent fatal invalid reference errors in v7.1.7
return;
}
Use code with caution.Option B: Disable the Broken HookIf you don’t want to add a method, you can simply stop the plugin from trying to call it.Open revslider/admin/revslider-admin.class.php.Locate line 575:phpadd_action(‘admin_footer’, ['RevSliderAdmin', 'add_ajax_footer_functionality']);
Use code with caution.Comment it out or delete it entirely:php// add_action(‘admin_footer’, ['RevSliderAdmin', 'add_ajax_footer_functionality']);
Use code with caution.

Invalid reference:
revslider/admin/revslider-admin.class.php:575
add_action(‘admin_footer’, ['RevSliderAdmin', 'add_ajax_footer_functionality']);

The definition of the add_ajax_footer_functionality method is missing from the entire ZIP.
The same issue exists in 7.1.6 and causes a PHP Fatal Error in wp-admin.

Revslider updated, no issues known with WP version 7.1.

https://www.php.net/supported-versions.php