The roadmap can be viewed on the Jira project dashboard.
Discussion for Fabric releases happens on the #fabric-release channel in RocketChat.
See prior release notes for release history and content. Prior release documentation can be found in the documentation links.
Beginning with the 1.2.0 release, the Fabric maintainers plan on publishing quarterly, focused releases that target a small number of themes for improvements and new features.
We maintain a JIRA release dashboard for the upcoming release. The top left gadget on the dashboard indicates which Epics are currently in progress for the upcoming release.