Why does my phone app constantly freeze after upgrading to ios 10.x?

After upgrading to ios 10, and then 10.1, 10.1.1 my phone app freezes all the time. killing then restarting the app allows me to place a call. After a quick web search this seems to be a widespread and as yet unrecognized problem with all the 6 serries iphones. It seems like the only fix is to go back to 9.3.5 then the problem goes away.