The release schedule for the GNOME 3.20 series has been published
GNOME 3.19.x is an unstable development series intended for testing and hacking purposes. GNOME uses odd minor version numbers to indicate development status, so this unstable 3.19.x series will become the official 3.20 stable release. There are many ways you can get involved.GNOME 3.20 Release Schedule
Maintainers document plans for this release on the RoadMap. These plans do not necessarily cover every module and every feature that will be worked on, nor are they guaranteed to arrive in time.
When we are near feature-freeze, please mention the new features for the /ReleaseNotes.