Bria 4 was released in 2014. Bria 5 has been around since Jun 2017. I'd definitely give the company a break here.
When v4 didn't work with the betas of HS, I would expect them to warn new buyers that they won't be fixing v4. I would also expect them to have a grace period where recent buyers of v4 get a free upgrade to 5.
I don't know the details of whether or not they did any of the above. Just pointing out a (more) fair approach.
Either way: no. Your product supports a platform, you update it to be compatible. If you don't want to support the new version, that's your choice.
https://support.counterpath.com/knowledge-base/article/%E2%8...
I did my homework, yes I missed out on the free upgrade, but 30% discount ain't bad and with the frequency that they upgrade their softphone versions I think its way more fair than Parallels or other software where you pay $50 every year with very few updates in between.