diff --git a/include/types/server.h b/include/types/server.h
index 745a94f..039fd89 100644
--- a/include/types/server.h
+++ b/include/types/server.h
@@ -47,7 +47,7 @@
 #define SRV_CHECKED	0x0010	/* this server needs to be checked */
 #define SRV_GOINGDOWN	0x0020	/* this server says that it's going down (404) */
 #define SRV_WARMINGUP	0x0040	/* this server is warming up after a failure */
-/* unused: 0x0080 */
+#define SRV_MAINTAIN	0x0080	/* this server is in maintenance mode */
 #define SRV_TPROXY_ADDR	0x0100	/* bind to this non-local address to reach this server */
 #define SRV_TPROXY_CIP	0x0200	/* bind to the client's IP address to reach this server */
 #define SRV_TPROXY_CLI	0x0300	/* bind to the client's IP+port to reach this server */