diff --git a/upnp/inc/upnp.h b/upnp/inc/upnp.h
index 8508a47..894702e 100644
--- a/upnp/inc/upnp.h
+++ b/upnp/inc/upnp.h
@@ -1492,7 +1492,7 @@ EXPORT_SPEC int UpnpAcceptSubscriptionExt(
 	 * Plug and Play Device Architecture specification. */
 	IXML_Document *PropSet,
 	/*! [in] The subscription ID of the newly registered control point. */
-	Upnp_SID SubsId);
+	const Upnp_SID SubsId);
 
 /*!
  * \brief Sends out an event change notification to all control points
diff --git a/upnp/src/api/upnpapi.c b/upnp/src/api/upnpapi.c
index 2a24b52..f231f67 100644
--- a/upnp/src/api/upnpapi.c
+++ b/upnp/src/api/upnpapi.c
@@ -2522,7 +2522,7 @@ int UpnpAcceptSubscriptionExt(
 	const char *DevID_const,
 	const char *ServName_const,
 	IXML_Document *PropSet,
-	Upnp_SID SubsId)
+	const Upnp_SID SubsId)
 {
 	int ret = 0;
 	int line = 0;