Alan, I thought I'd share this here, and ask for your thoughts.
As I wrote earlier, the problem I've had is that after several minutes of not actively using Cheogram, when someone calls me my phone rings far too long after the caller has already hungup, but this happens only when relying on cell service, I've never been able to make this problem happen on wifi.
The jmp folks told me they believe that, for some reason, Cheogram was "losing its connection". Not exactly sure what that means, and they didn't offer to do anything about it. So, I didn't/don't know if it is a Cheogram problem, or a Graphene problem..... or both, or neither.
I hit upon this idea to test things, and to rely on as a workaround until some smart person fixes this. (The workaround I need is to somehow make my phone reliably ring without delay when I am called.)
I already had Cheogram running, using xmpp account X , but of course suffering with this problem we're discussing. I installed the Snikket app on my phone, and connected it to the same account X. Then, I waited several minutes when I knew I'd have the problem with Cheogram losing its connection and not ringing for a call. Then I called my phone. As expected, the Cheogram app did not ring. But, Snikket did immediately. So, from this, I concluded that (A) There likely is something wrong with Cheogram, and not Graphene; and, (B) In the short term my workaround is to turn on my xmpp account X in Snikket when I'm relying on cell service.
Interested in your thoughts on my test and conclusion before I turn to the jmp support people with this.