Questions on Versioning Problems of WS-SecureConversation

It looks like the new version of WS-SecureConversation (WS-SC) v1.4 does not have any schema changes. The schema link points to ws-secureconversation-1.3.xsd.  If this is the case, then this is a very bad design for this standard on the versioning. There is no way to tell from the incoming message whether this is a WS-SC v1.4 message or a WS-SC v1.3 message. We cannot use namespace in the message to make the differentiation. The question is: why to publish a new version without schema change? 
 

Eclogue Chang