My old phone is an X and I'll be keeping it for a backup. I was just going to move the simm to the 13 but was told that it would not support 5G. So last week I picked a 5G simm and installed it in the X and it worked fine. The plan is to use the 5G simm in the X when I'm out boating or off road biking. If my Pro Max ever shows up, I'll report how it went with the change out.