I've just received my brand new Ubuntu phone from Meizu.
Does anyone know if the phone supports SIP nativly, for caller and text app?
As far as I can figure out (having spent several years of looking), no it does not (shame).
I think there would be demand for it, and as there are Javascript SIP libraries, I do not think it would be too difficult, but I have not yet been able to find even an installable app for it. Not having any experience programming SIP apps, I would not know where to start, but if someone wants to help, maybe there will be soon!