Hi, The current check in MPICH forcing to use exactly the same GCC version to build MPICH and the user programs is too restrictive. I got bitten by this and seems to be a recurrent problem, for example, see https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=807666 The check was added many years ago by a problem with GCC3, so I think it could be safely removed. Please see attached patch. Cheers, Ana -- Ana Guerrero Lopez HPC Team - SUSE Labs