Hello,
later today I plan to package v3.1.6 as the last release in 3.1.x series. Based on our release policy to work on latest two stable branches, 3.1 got out of by release of 3.3.0.
The branch 3.1 may still get patches, it is not a closed branch, but it is a matter of developers for willing to do that -- it is just not going to be packaged again in a numbered release, so people will have to use git branch.
Cheers, Daniel