Release 2.0.3 is a maintenance release on the 2.0.x branch and solves a few bugs, see: http://goo.gl/2Hyv7c
We encourage all the users to upgrade to this version.
Release 2.1b is a brand new release that contains several new features, including a full tutorial, see: http://goo.gl/22zpFI
We invite users to try it and provide feedbacks. Among other things, we would like to have feedbacks on the new autoconf procedure (./configure script) so as to be sure that it is portable on a large number of different systems.
You can find both releases in the download section of the plumed webpage. They are also tagged on git (v2.0.3 and v2.1b).
For those of you using the master branch on git: you might want to switch to the v2.1 branch, since we will start soon to add possibly unstable features on the master branch.