Fatal error after last update

I got this error after last update:

[24-Aug-2018 15:12:57 UTC] PHP Fatal error: Class ‘Genesis_Admin_Boxes’ not found in …(removed this part of URL for security)/public_html/wp-content/plugins/wpstudio-testimonial-slider/inc/gts-admin.php on line 16

I was using this plugin in a widget area on my home page for one of my sites and got a white screen of death. Checked wp error logs and this was the cause. When I removed the plugin, problem gone. I’m not sure where this class is being called from, but it definitely is NOT on that doc in line 16.

This plugin needs an update for sure. Please let me know when that can be. Thanks

Micha

The page I need help with: [log in to see the link]