Arq 2.6.8
In my haste to fix this customer problem, I didn’t do enough testing on 2.6.3-4. I screwed up. There was a bug in those releases where some objects were marked as “compressed” but they weren’t actually compressed. So Arq couldn’t restore properly.
What really made things bad was that at some point in my rush to get the issue fixed I accidentally (because of muscle-memory habit) ran the command to publish 2.6.3 in the “update stream” as an official release of Arq, which meant that everyone who happened to check for updates would get this buggy version. I didn’t realize this for several hours. At that point I could only move forward and fix things as quickly as possible.
Most developers have screwed up a release. The good ones are transparent about it and fix things promptly. As a registered user, I received an e-mail about this issue, and when I had a question he replied in literally one minute. Arq is my favorite new app of the last couple years.