--- chan_sip.c.orig	2008-01-31 20:52:49.000000000 +0100
+++ chan_sip.c	2008-07-11 20:21:16.000000000 +0200
@@ -15456,7 +15456,7 @@
 {
 	time_t t = time(NULL);
 
-	if (ast_test_flag(&peer->flags[1], SIP_PAGE2_SUBSCRIBEMWIONLY) &&
+	if (!ast_test_flag(&peer->flags[1], SIP_PAGE2_SUBSCRIBEMWIONLY) ||
 	    !peer->mwipvt) {	/* We don't have a subscription */
 		peer->lastmsgcheck = t;	/* Reset timer */
 		return FALSE;