Hi, We did not bump the major version because MPIX_Mutex interfaces were "experimental" in nature. Our position is that we update the ABI version based on official MPI standard functionality only. Ken On 1/6/21, 3:55 AM, "Alastair McKinstry via discuss" <[email protected]> wrote: Dear MPICH developers, I see that MPICH 3.4 has been released - Happy New Year and congratulations to all involved. I'm one of the Debian Maintainers of MPICH, and have a question though : should the SOMAJOR version not have been increased? From the CHANGES log, the following look concerning: # Change the signature of MPID_Init to include requested and provided thread levels. # Remove support for logical reduction operations on floating point types. # Remove MPIX_Mutex interfaces. Typically when functionality is removed from a library, or signatures change, the major version is incremented (the minor version can be for additions, such as the other functionality added. Are these changes purely internal to MPICH, or has the ABI changed ? This matters to the distributions such as Debian because we ship the shared libs based on SOVERSION; ie the binary package "libmpich12" currently contains libmpich.so.12.18 and libmpich.so.12 , and if mpich 3.4 is packaged as-is, will contain libmpich.so.12.1.9 (ansd symlink libmpich.so.12) and it is necessary for applications to be able to use this as a drop-in replacement. On seeing these changes in the release logs, I had been anticipating that the next version would be libmpich13.0.0 (or similar), shipped in "libmpich13". This enables upgrades; both libmpich12 and libmpich13 can co-exist. Can you confirm whether the ABI changes, and this is a drop-in replacement ? Regards Alastair McKinstry -- Alastair McKinstry, <[email protected]>, <[email protected]>, https://diaspora.sceal.ie/u/amckinstry Misentropy: doubting that the Universe is becoming more disordered. _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss