diff --git a/repmgr.h b/repmgr.h
index 53e7874b..e91d0f1f 100644
--- a/repmgr.h
+++ b/repmgr.h
@@ -77,6 +77,9 @@
 #define MIN_SUPPORTED_VERSION		"9.3"
 #define MIN_SUPPORTED_VERSION_NUM	90300
 
+#define MAX_UNSUPPORTED_VERSION		"12"
+#define MAX_UNSUPPORTED_VERSION_NUM	120000
+
 #define REPLICATION_TYPE_PHYSICAL 1
 #define REPLICATION_TYPE_BDR	  2