One of the goals in the roadmap is to move part of Fabric's functionality into another library (Invoke), which does have recent activity and supports Python 3.
Unfortunately, the main dev has been saying that he'll be releasing a rewrite with Python 3 support "at the end of the month" for the past 2-3 years. There's actually a fork ("Fabric3") which fully supports both Python 2.7 and Python 3.4+, but the Fabric dev refuses to merge in any PRs that have been submitted to help with Python 3 support. It's somewhat infuriating.
One of the goals in the roadmap is to move part of Fabric's functionality into another library (Invoke), which does have recent activity and supports Python 3.