Please read the comment in this issue on Github.
Matias (the Lead G5 Developer) said that there is no release date scheduled yet, but it seems that they are actively working on it.
Yeah damn, thats what i found too.
I did hope, maybe you got some insider news.
We are also waiting for Gantry 5.5 Stable to be released so we can do the final work and release the Joomla 4 version of our templates.
Same here. One question: When i start building a new site with the dev build of g5, i should be able to simply upgrade it when a stable version is released right?