Index: write.c
===================================================================
--- write.c	(revision 31092)
+++ write.c	(revision 31093)
@@ -515,6 +515,9 @@
 	else
 		lht_dom_hash_put(obj, dummy_node("enforce_clearance"));
 
+	if ((wrver < 7) && (poly->enforce_clearance > 0))
+		pcb_io_incompat_save(NULL, poly, "enforce_clearance", "lihata boards before version v7 did not support polygon side enforce_clearance\n", "Either save in lihata v7+ or set polygon enforce_clearance to 0");
+
 	geo = lht_dom_node_alloc(LHT_LIST, "geometry");
 	lht_dom_hash_put(obj, geo);