Running the UCP upgrade upgrades all managers and workers to the new version, contrary to what is described here. Here is sample output from running this command:
$ docker container run --rm -it --name ucp -v /var/run/docker.sock:/var/run/docker.sock docker/ucp:2.2.12 upgrade --interactive
Unable to find image 'docker/ucp:2.2.12' locally
2.2.12: Pulling from docker/ucp
a073c86ecf9e: Already exists
fae35fe3a426: Pull complete
f13c1be613a6: Pull complete
Digest: sha256:61d4a2e8969a0139187ecf13af8c0020bb7bb5ff5efa2b06e331394a67bd4b68
Status: Downloaded newer image for docker/ucp:2.2.12
INFO[0000] Your engine version 17.06.2-ee-16, build 9ef4f0a (4.4.0-133-generic) is compatible
INFO[0000] Upgrade the UCP 2.2.5 installation on this cluster to 2.2.12 for UCP ID: sc3nkn5p6rnc33o1e33mnqa1r
INFO[0000] Once this operation completes, all nodes in this cluster will be upgraded.
Do you want proceed with the upgrade? (y/n): y
Maria Bermudez