I am using a Samsung Captive Glide operating on ICS 4.0.4. All my other apps are working fine. I have gone through all the trouble shooting measures including force stop the app, uninstall and reinstall, calling tech support, etc. Tech supports answer was to buy a new phone. My response was, support the app that I am paying for. I have older apps and free apps that all work without issues on my phone. ICS is only 4 years old.
So far a temp fix I have found was to find an older APK of the RC app, even older than the current version I already have installed on my phone. The version I has was 7.5, the version I downgraded to was 7.4. The issue happens when the phone app tries to connect the call in HD. Unfortunately I don't know if the call will try to be connected in HD or SD until after I answer the call. As you can imagine that is extremely frustrating as well as unpredictable and unprofessional. The only way to temporarily stop incoming calls from answering in HD is to go to Settings, Apps, Locate the RC app to Force Stop then go back to the RC app to open it again. This is a very temp solution and only seems to work for 2 or 3 calls after before connecting in HD again. Tech support said there is no way to prevent the phone app from answering in HD. If they could simply fix that one issue the older version of the RC app I downgraded to would work just fine in theory.
I currently have the Ring Central Office plan.