@Cris70 I had issues updating from the repo as well, I had to update the key with curl -s https://packages.gitlab.com/gpg.key | sudo apt-key add -
I tried to do the 16.7.7 upgrade from 16.6.7, and I got a failure during the installation, I made a separate post about it at Upgrade from 16.6.6 to 16.6.7 ruby/glibc issue and am trying to figure out what exploded.