There was a bug that caused the plugin to crash and print an error for some users while during its start process. It was caused because of a safety mechanism that prevents invalid or weird items to be set as the icon of a warp. As the plugin tried to parse the icons it didn't care if the item was broken or not and set it as the icon anyway. By that the safety mechanism blocked it and caused the crash that's getting fixed with this update.

But why did it only occur after the update?
Well, that bug actually already existed before. But as we've added native support for 1.13+, which renamed all materials due to " The Flattening", the items that worked before changed to be invalid for the system to process.

In a nutshell the bug is fixing a crash which most 1.13+ users got to see after updating to 2.2. Thanks to @mechcalvin for reporting the bug.