Read release notes (be sure to click the release version heading to see the full notes).

Check out the (brief) generic release notes on joinmastodon.org

Make sure you have a copy of https://gitlab.com/sunbeam.city/mastodon/ cloned locally.

export NEW_VERSION=4.5  # change to actual new version, beware wacky branch naming scheme??
git fetch upstream --tags
git checkout sunbeam-changes
git rebase stable-$NEW_VERSION
# fix some probably annoying merge conflicts
git push -f

Then check the "Jobs" page on Gitlab, and you should see the Docker image build happily running 🏃 It takes about 8 minutes.

SSH to the server (arkology.sunbeam.city).

Then run:

cd /var/services/mastodon
sudo -u services git pull
sudo -s
docker-compose pull && \
  docker-compose down && \
  docker-compose up -d
docker-compose run --rm -e SKIP_POST_DEPLOYMENT_MIGRATIONS=true web bundle exec rails db:migrate