Arq Backup 6 was just released. It is really compelling software if you want to “roll your own” backup service, rather than use something tightly integrated with the back-end, like BackBlaze.
I’m very glad, now, that I bought a lifetime license when Arq Backup 5 came out, four years ago. I got a free (as in, already paid for) upgrade!
Arq Backup 6 is much simpler looking than prior versions were. It is set up almost like a web app. Unfortunately, it no longer looks and feels much like a Mac app, which is one of the things that brought me to it in the first place. I don’t use its main UI that much anyway, though, so that probably is not a big deal.