so that we can use the maven artifact instead of adding binaries to the repo?
Binaries are added to the repo anyway. Tinder and stringprep.jar are here:
Openfire/build/lib/merge at master · igniterealtime/Openfire · GitHub
Artifact versions are maintained in this file:
Openfire/versions.txt at master · igniterealtime/Openfire · GitHub
So there's no need to wait until it's available on Maven Central, because Openfire doesn't use it anyway (unfortunately).
@Konstantin, you could therefore go ahead and prepare a pull request which contains the new stringprep.jar and an updated versions.txt.
If the new jar requires a Tinder update, you would also need to update Tinder first, make a PR for Tinder and then a PR for Openfire containing the new tinder.jar.