The roadmap can be viewed as a list of GitHub issues with Epic label.
Discussion for Fabric releases happens on the #fabric-release channel in chat.
See prior release notes for release history and content. Prior release documentation can be found in the documentation links.
The Hyperledger Fabric maintainers produce quarterly minor releases several times a year to deliver the release themes on the roadmap as they become ready, along with other smaller features, improvements, and fixes.