I have a 4 lines (4 query replace actually) change that would

 * make the last OpenMPI release (4.0) supported by Boost.MPI (2 MPI_Address -> MPI_Get_address), right now it wont compile as the 4.0 version enforce the obsolescence of MPI_Adress

 * make MPI implementation with o Fortran support supported (2 MPI_INTEGER->MPI_INT)

Sorry for the late notice, is it toot late to merge those 2 on release ?