The algorithm for validating user names was modified and some users may have invalid names. The command `forgejo doctor --run check-user-names` will list all of them so they can be renamed.
If a Forgejo instance has users or organizations named `forgejo-actions` and `gitea-actions`, they will also need to be renamed before the upgrade. They are now reserved names for the experimental internal CI/CD named `Actions`.
Since v1.18.5, in addition to the Forgejo release number, a [semantic version](https://semver.org/#semantic-versioning-200) number (e.g. `v3.0.0`) can be obtained from the `number` key of a new `/api/forgejo/v1/version` endpoint.
Now, it reflects the Gitea version that Forgejo depends on, is no longer prefixed with `v` (e.g. `3.0.0+0-gitea-1.19.0`), and can be obtained from the `version` key of the same endpoint.