Tetris Effect Connected has been updated to version 1.19 today by Enhance. You can find out the complete patch notes for this update from here.
This update appears to have made minor adjustments like changing the session timeout from 45 to 60 seconds so that the network code leads to fewer errors during bad connections. There are other bug fixes included and some minor adjustments. You can take a look at the complete details below, or you can have a look at them on the Steam forums.