Hi,
You want to be using commands like in the docs here: Update GitLab installed with the Omnibus GitLab package | GitLab
apt upgrade gitlab-ee=12.0.12-ee.0
so replace gitlab-ee with gitlab-ce if you are using the ce version and also change the version number accordingly. Your upgrade path as per the docs is:
13.12.Z -> latest 14.0.Z -> 14.1.Z -> latest 14.Y.Z
so you want to install the latest 13.12.x release, wait for background migrations to finish, then install the latest 14.0.x release and wait for background migrations to finish, and then to latest 14.1.x release which is currently 14.1.1 as of today.
If that is failing to work, then you might need to refresh the repo data, so that will mean running a command like this:
curl https://packages.gitlab.com/install/repositories/gitlab/gitlab-ee/script.deb.sh | sudo bash
I had to do this once when I couldn’t upgrade from 12.9.x release and only manually running the above command helped me get around it - again make sure you change gitlab-ee to gitlab-ce if running the ce version. This is important since otherwise you will upgrade gitlab-ce to gitlab-ee if using the link above, or potentially also downgrade from gitlab-ee to gitlab-ce which if not done properly can be problematic. So make sure you use the correct url based on the version installed.
If you are unsure which version you have do:
dpkg -l | grep gitlab
it will then show you either gitlab-ce or gitlab-ee as being installed.