Hello 🙂
It might be best you review the Release Notes to see what specific changes were made so you can update your code as needed. It also might be helpful to update sequentially from 4.0.4 to 4.4.2, checking the Events > Settings > Help > Recent Template Changes section for another frame of reference.
Other than that there’s not much I can provide in regards to support. Customizations to our plugins need to be handled by users. Please review our What support is provided for license holders? Knowledgebase article for more information.
If you run into any conflicts along the way, be sure to review the Testing for conflicts guide to rule out theme and plugin conflicts. It’s always best to test with WP_DEBUG and WP_DEBUG_LOG enabled on your site’s wp-config.php file. Any errors will display at the top of your page as you try to reproduce the conflict.
I also recommend right-clicking your mouse and opening the ‘Inspect’ tool to see if any errors display in the console. Note what you find in addition to providing your System Information as a private reply and I’d be happy to help further troubleshoot.
Thanks and please keep me updated. Cheers!