diff --git a/Custom_MNS/flexible_custom_hierarchical_mns.py b/Custom_MNS/flexible_custom_hierarchical_mns.py
index 8e102c05052bdc84e624c70376f2e6a451ed74a0..ab4e2e24a6db6a021a93c4e6b841b0b56ca2fbf3 100644
--- a/Custom_MNS/flexible_custom_hierarchical_mns.py
+++ b/Custom_MNS/flexible_custom_hierarchical_mns.py
@@ -50,7 +50,7 @@ COMP_RELEVANT_VERSIONS = {
 # Allow to reuse the stacks from other MPIs
 SWAPPABLE_MPIS = {
     'BullMPI': ('OpenMPI', None),
-    'impi': ('psmpi', '5.6'),
+    'impi': ('psmpi', '5'),
 }
 
 # MPI relevant version numbers