1. Merge `debian/buster` into `debian/bullseye`. There will be a merge conflict in the changelog. You will need to accept the new changelog entry from debian/buster, but change the version from `+deb10` to `+deb11`.
1. commit
1. clean merge files with `git clean -f`
1. Tag the debian branch with
```
gbp tag --debian-branch=debian/buster
```
1. Push tags back to gitlab.
1. (optional) go start build in jenkins: Debian10/advLigoRTS
1. Look for version update in: https://apt.ligo-wa.caltech.edu/debian/buster_status.txt
