Has it been disabled or discontinued? I downloaded it a few months ago but never got it to work* so I forgot about it. Now I can't even find it in either app store. If it's not available, why is it still advertised (by Support / Home phone / Calling features / Home Phone App)?
*(I never got it to work because even though I'm on PureFibre, I've always gotten a "not available in your area" error trying to connect.)