Source : Free On-Line Dictionary of Computing

forward compatibility
     
         The ability to accept input from later versions of
        itself.
     
        Forward compatibility is harder to achieve than {backward
        compatibility}, since, in the backward case, the input format
        is know whereas a forward compatible system needs to cope
        gracefully with unknown future features.  An example of future
        compatibility is the stipulation that a {web browser} should
        ignore {HTML tags} it does not recognise.
     
        See also {extensible}.
     
        (2003-06-23)