diff --git a/sys/netgraph/netgraph.h b/sys/netgraph/netgraph.h
index e83f61d3f60..10db352e0fa 100644
--- a/sys/netgraph/netgraph.h
+++ b/sys/netgraph/netgraph.h
@@ -69,11 +69,20 @@
  * modules.
  */
 #define _NG_ABI_VERSION 12
-#ifdef	NETGRAPH_DEBUG /*----------------------------------------------*/
-#define NG_ABI_VERSION	(_NG_ABI_VERSION + 0x10000)
-#else	/* NETGRAPH_DEBUG */ /*----------------------------------------------*/
-#define NG_ABI_VERSION	_NG_ABI_VERSION
-#endif	/* NETGRAPH_DEBUG */ /*----------------------------------------------*/
+
+#ifdef	NETGRAPH_DEBUG
+#define	_NG_ABI_PREFIX1 0x10000
+#else
+#define	_NG_ABI_PREFIX1 0
+#endif
+
+#ifdef	INVARIANTS
+#define	_NG_ABI_PREFIX2 0x20000
+#else
+#define	_NG_ABI_PREFIX2 0
+#endif
+
+#define NG_ABI_VERSION	(_NG_ABI_PREFIX1 + _NG_ABI_PREFIX2 + _NG_ABI_VERSION)
 
 /*
  * Forward references for the basic structures so we can