diff --git a/src/core/session.c b/src/core/session.c
index c773c37d..e74b4774 100644
--- a/src/core/session.c
+++ b/src/core/session.c
@@ -39,6 +39,7 @@ void session_set_binary(const char *path)
         irssi_binary = path;
 }
 
+/* SYNTAX: UPGRADE [<irssi binary path>] */
 static void cmd_upgrade(const char *data)
 {
 	CONFIG_REC *session;