diff --git a/include/types/proxy.h b/include/types/proxy.h
index 8348f92..92517ca 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -123,7 +123,15 @@
 #define PR_O2_LOGHCHKS	0x00000800	/* log health checks */
 #define PR_O2_INDEPSTR	0x00001000	/* independant streams, don't update rex on write */
 #define PR_O2_SOCKSTAT	0x00002000	/* collect & provide separate statistics for sockets */
-#define PR_O2_AS_REQL	0x00004000      /* appsession: learn the session id from the request */
+
+/* appsession */
+#define PR_O2_AS_REQL	0x00004000      /* learn the session id from the request */
+#define PR_O2_AS_PFX	0x00008000      /* match on the cookie prefix */
+
+/* Encoding of appsession cookie matching modes : 2 possible values => 1 bit */
+#define PR_O2_AS_M_PP	0x00000000      /* path-parameters mode (the default mode) */
+#define PR_O2_AS_M_QS	0x00010000      /* query-string mode */
+#define PR_O2_AS_M_ANY	0x00010000      /* mask covering all PR_O2_AS_M_* values */
 
 struct error_snapshot {
 	struct timeval when;		/* date of this event, (tv_sec == 0) means "never" */