Hi @hastygitlab
I had similar issues when mine got stuck on 12.9.2. See this post where I explain how to go forward:
first you want to download the script.deb.sh and run it so that it refreshes your repository information. Then you can run the manual upgrade commands specifying the actual version to upgrade to. Since you are on an older version you will have to go through quite a few upgrades to get to the latest. This link should help for that:
Based on that info it could be something like this:
11.11.8 → 12.0.12 → 12.1.17 → 12.10.14 → 13.0.14 → 13.1.11 - > 13.5.3
of course please ensure you have backups in case anything goes wrong with the upgrade process. You will also see that postgres will be upgraded through some of these releases as it is required. If you are using the omnibus package, I expect you have the default bundled postgres. If you were using an external postgres db, then you would need to take care of that manually since omnibus won’t do it.