diff --git a/servers/slapd/overlays/syncprov.c b/servers/slapd/overlays/syncprov.c
index 95deb6d5f4..aab00da1ff 100644
--- a/servers/slapd/overlays/syncprov.c
+++ b/servers/slapd/overlays/syncprov.c
@@ -28,6 +28,10 @@
 #include "config.h"
 #include "ldap_rq.h"
 
+#ifdef LDAP_DEVEL
+#define	CHECK_CSN	1
+#endif
+
 /* A modify request on a particular entry */
 typedef struct modinst {
 	struct modinst *mi_next;