How much backwards compatibility ?

[Jody Goldberg <jody gnome org>]

While testing the minor change to the xml that I mentioed previously
I noticed that the change is actually backwards compatible for file
i/o.  However, we use the same format for inter-process copy/paste
where it would not be backwards compatible.

So older versions would be able to read files from > 1.0.3
but not receive a paste from the clipboard.  Should we worry about
this ?