
Thanks to mosimchah for the amazing AICP.
Just dirty flashed the 20190417 13.1 rom basing off on an earlier 13.1 build. Everything looks fine. Wifi calling on Tmobile USA still works. However, Titanium Backup still crashes. Don't know why. Anyone has the same issue with Titanium backup ?
I see that mosimchah is using the same carrier as mine and recommends Pie. I am kinda timid in the Pie upgrade as I really need the Volte and wifi calling. The AICP 14.0 thread has many failed wifi calling and volte cases, though.

Any exception?