Bria 5 appears to have been released in June.[0] It supports MacOS High Sierra, released three months later.

Bria 4, released in May 2014[1], will not. It presumably runs on Mavericks (2013), Yosemite (2014), El Capitan (2015), and Sierra (2016), and possibly older releases, but not High Sierra.

The question is whether that's reasonable or not.

I don't know. I can understand being frustrated, for sure. That's also a pretty long lifecycle, with a clear upgrade path.

If you choose to update to High Sierra, knowing it breaks v4... maybe stay with Sierra?

I don't feel strongly about it, though.

[0] http://www.counterpath.com/counterpath-announces-release-of-... [1] http://www.counterpath.com/counterpath-launches-bria-4-softp...