I have Timg. I don't know anything about IMS. I didn't know about it until you mentioned it. Someone else will have to help you with that.When I go to my phone status IMS is not registered. And when I get a call or receive a call the phone disables data and says it using 2g for voice. When the call ends it goes back to LTE data and Voice. Either the phone is messed up or something wrong with the sim or LOS 20 is severely messed up. I ordered a new Sim from Ting to see what happens.