Someone brought to my attention that ArraySync was no longer activating for them. I looked into the issue and it appears the hosting provider for the activation server automatically updated PHP to 7.x, which broke the activation scripts.
I have now rolled it back to PHP 5.6 and the activations should be working again. Sorry if anybody else encountered this same issue!
Please keep in mind ArraySync has been discontinued for several years now, and will no longer receive updates. It will not run on macOS Catalina or higher, and will definitely not run on the new ARM Macs.
I plan to create a completely new app that does something similar to ArraySync in the future, but cannot guarantee any specific timeframe.