From July 2023 Docker Compose V1 stopped receiving updates, Docker Compose v2 is nowadays widely available, as in the latest Ubuntu LTS.

It is time to drop support of v1 for mirrors and make use of the new features of v2.

The same will also apply to test setup and development setup.

Rather than upgrading the current compose v1 files in musicbrainz-docker, we are more likely to create brand new compose v2 files in the main repository musicbrainz-server. That would imply reinstalling mirrors from scratch though.