Please do not use apt at all, we are doing image-based upgrades, and have a channel concept:

stable channel for all users release candidate (RC) for testers and devs, and ambitious users devel for developers

when using apt you would update to latest packages in devel, that might break your phone or has other complications. This is not a desktop distro!

Solution: Change to another channel briefly or reinstall UT with the installer. That will fix your issue.

BR Florian