They've kept it quiet - but it happened. The Joomla core developers released Joomla! 4.0.0 Beta 1 - very very quietly. I only noticed because I was looking over the update XML file for the alpha 12 version - and there it was.
You can get it here: https://developer.joomla.org/nightly-builds.html
Starting tomorrow, I'll be updating my extensions for Joomla! 4. These new versions will ONLY be modified for Joomla 4 beta1, and will remain uncertified for later beta releases until I have the chance to test them. It's going to be slow going at first, but once completed, further beta versions will get certified shortly after each beta comes out.
There's an added bonus to developing for the beta versions; I get to play with the new API. I already have work that's been waiting for J4 to hit beta.
Things are about to get awesome! I've been looking forward to this.
First extension up - AdminExile