Current version of MrBayes is 3.2.3, released October 22, 2014.
All downloads of MrBayes are managed through the MrBayes download page on SourceForge. You can download executable versions for Windows (32bit and 64bit), and Macintosh (64bit) computers, as well as the source code for compilation on Unix machines. The Mac installer includes both the serial and parallel (MPI) version of the program, while the Windows installer only includes the serial version; both include the BEAGLE library (v2.1). The serial version works well for smaller analyses but if you plan to run large analyses using many parallel chains, you should use the MPI version instead. Refer to the User Manual for help with installation of the program.
You can get access to older releases from here.
You may also download cutting edge developer version of MrBayes from the svn repository hosted at sourceforge. Note that you have to compile the code yourself. Read instructions in README file in the root directory of the svn repository for further instructions.
A great aid for resolving problems with MrBayes is the MrBayes
If you have a question about MrBayes you can ask it by posting the question to the mailing list. To post on this list you
have to be subscribed to it. However, the list archive
is accessible to everyone.
The list will also be used by the MrBayes authors for announcements of new versions or bugfixes.
We, therefore, recommend that you subscribe to the list if you are a regular MrBayes user.