Release Notes: This release marks the transition of the "feature" 1.5 series to "super stable" status. No new features will be added to 1.6; the emphasis in the 1.6 series will be bugfixes and stability. Many fixes to processor/memory affinity. New support for ARM5/6. MXM fixes. Enabled fakeroot builds. VampirTrace updates. A fix for "mpirun --stdin all". Dropped support for OS X Tiger. Properly handles Fortran .FALSE. values in attribute functions. Fixes some C++ API issues. Fixes default hostfile MCA parameter behavior. Ensures not to touch port_name in MPI_CLOSE_PORT.
Release Notes: Process affinity is now used by default. Support was provided for all remaining MPI-3 functionality except MPI-3 one-sided semantics: all remaining non-blocking collectives, neighborhood collectives, const and  array notation, non-blocking communicator duplication, and non-collective communicator creation. SCIF communication support with the Intel Phi was added. New Java MPI bindings were provided. Bugs in the mpi_f08 module were fixed. A newer version of ROMIO is used. Many, many small bugs were fixed across the code base.
Release Notes: Improvements to Torque, SLURM, and CUDA support, various Solaris fixes, full support for MPI 2.2, fixed MPI_IS_THREAD_MAIN behavior, various rank file fixes, fixed iWARP support, and MPI-3 support for MPI_Count and MPI_T control and performance variables. Support for ancient OS X systems was dropped. An obscure pack/unpack datatype bug was fixed. PMI2 support was added.
Release Notes: Many bugs fixed in version 1.6.5 were forwarded-ported. This release integrated MXM STREAM support for MPI_ISEND and MPI_RECV, added PCI device distance mapping, fixed parallel debugger attachment functionality, fixed datatype corruption when combining certain datatypes, added Location Aware Mapping Algorithm (LAMA) for process affinity support, and fixed MPI_STATUS handling in obscure cases.
Release Notes: A compilation error when --without-memory-manager was specified was fixed along with an XRC compile issue in OpenFabrics support.
Release Notes: This release added much new MPI-3 functionality: matched probe, MPI_TYPE_CREATE_HINDEXED_BLOCK, non-blocking collectives, Fortran '08 bindings, MPI_INFO_ENV, and MPI_GET_LIBRARY_VERSION. Compile-time warning of deprecated functions was enabled. Various performance improvements were made throughout the codebase. MPI_TYPE_CREATE_F90_REAL was fixed. Many MXM and FCA updates were made. The run-time support layer. was revamped. Windows and checkpoint/restart support was dropped. MPI collective performance was improved.