[Edited]
End of Sales for SPA phones is not announced, and probably still far away until their sales will decline enough to justify. Of course, discontinuing UC320 and UC500 is a perfect way for Cisco to sell much less SPA phones.
If Cisco really wants their SPA phone customers to all go 3CX, Digium or whatever, that is their unfortunate choice.
Personally, I'm not affected, because I've never sold not even one of these, as to me they looked inferior and short-lived since the beginning.