Now that Puppet Server 2.0 has been released, we should, assuming the 2.1.x branch CI jobs are all green, act on the latest plan from our branching document:
1) Do a non-fast forward merge up of the 2.1.x branch to the master branch, edit the README_BRANCHING.md document to indicate that only work toward 2.1 should be going to master right now and remove references to the 2.1.x branch. Submit a PR for that work up to the master branch.
2) Submit a separate PR to the stable branch with the same set of changes to README_BRANCHING.md as were submitted to the master branch.
3) Once the PR to master is merged and everything's green through CI, work with QE to delete the 2.1.x pipeline - probably involving the submission of a QE ticket with said intent - and subsequently delete the 2.1.x branch from the repo.