diff --git a/configure.ac b/configure.ac
index 496f7fd7..468d9d5f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -337,15 +337,11 @@ case ${ac_PRECISION} in
 esac
 
 ######################  Shared memory allocation technique under MPI3
-AC_ARG_ENABLE([shm],[AC_HELP_STRING([--enable-shm=shmget|shmopen|hugetlbfs],
+AC_ARG_ENABLE([shm],[AC_HELP_STRING([--enable-shm=shmopen|hugetlbfs],
               [Select SHM allocation technique])],[ac_SHM=${enable_shm}],[ac_SHM=shmopen])
 
 case ${ac_SHM} in
 
-     shmget)
-     AC_DEFINE([GRID_MPI3_SHMGET],[1],[GRID_MPI3_SHMGET] )
-     ;;
-
      shmopen)
      AC_DEFINE([GRID_MPI3_SHMOPEN],[1],[GRID_MPI3_SHMOPEN] )
      ;;
@@ -367,7 +363,7 @@ AC_ARG_ENABLE([shmpath],[AC_HELP_STRING([--enable-shmpath=path],
 AC_DEFINE_UNQUOTED([GRID_SHM_PATH],["$ac_SHMPATH"],[Path to a hugetlbfs filesystem for MMAPing])
 
 ############### communication type selection
-AC_ARG_ENABLE([comms],[AC_HELP_STRING([--enable-comms=none|mpi|mpi-auto|mpi3|mpi3-auto|shmem],
+AC_ARG_ENABLE([comms],[AC_HELP_STRING([--enable-comms=none|mpi|mpi-auto],
               [Select communications])],[ac_COMMS=${enable_comms}],[ac_COMMS=none])
 
 case ${ac_COMMS} in
@@ -375,22 +371,10 @@ case ${ac_COMMS} in
         AC_DEFINE([GRID_COMMS_NONE],[1],[GRID_COMMS_NONE] )
         comms_type='none'
      ;;
-     mpi3*)
+     mpi*)
         AC_DEFINE([GRID_COMMS_MPI3],[1],[GRID_COMMS_MPI3] )
         comms_type='mpi3'
      ;;
-     mpit)
-        AC_DEFINE([GRID_COMMS_MPIT],[1],[GRID_COMMS_MPIT] )
-        comms_type='mpit'
-     ;;
-     mpi*)
-        AC_DEFINE([GRID_COMMS_MPI],[1],[GRID_COMMS_MPI] )
-        comms_type='mpi'
-     ;;
-     shmem)
-        AC_DEFINE([GRID_COMMS_SHMEM],[1],[GRID_COMMS_SHMEM] )
-        comms_type='shmem'
-     ;;
      *)
         AC_MSG_ERROR([${ac_COMMS} unsupported --enable-comms option]);
      ;;