Breaks revslider

After updating revslider from 5.x to 6.x on a site with Themeco’s X theme, the slider revolution broke. That is, the slider loaded, but didn’t display anything. Widdled the cause down to this plugin. As soon as it was disabled, sliders worked again. I didn’t look into it more deeply, as this plugin is of little significance and hasn’t been updated for years. Just posting here in case it might help someone else.