Gutenberg is about to reach a milestone of having the technical and design vision in place. I know that we’re a little off from the existing roadmap, so I’d like to suggest an update to the milestones going forward. The milestones below are based on information from the focus leads about who will be available and when. As with all things in open source, these are best guesses and I encourage everyone to join us in being flexible as we keep creating:
Aug 2017 (late): Technical and design vision complete, iteration begins. This is in progress.
Aug 2017 (late): Testing plan begins: this will start with a public meeting.
Aug 2017 (late): Promotional page goes live for Gutenberg. This is in progress.
Sep 2017: Potential *.1 release with banner to encourage use of and feedback for Gutenberg
Nov 2017: 4.9 release
Dec 2017: Begin merge proposal for Gutenberg
Jan 2018: Gutenberg —> Customizer crossover (switching the focus)
It should be clear this is not set in stone. Gutenberg is not ready to merge and as a result giving it this time is important to iterate and respond to feedback. Beyond the merge proposal it’s also difficult to predict, so the roadmap to 5.0 isn’t