I asked this question as part of a reply to another posting,
so I thought I'd try it again.

My company has shipped a product built on 4.2, and we are currently
considering shipping the next revision on 5.0.  We've been doing
some compatibility testing, but we have been trying to find out
what Microsoft's official stand on all of this is.  I have searched
their web site and found lots of articulate marketing speak on how
fabulous 5.0 is, but I haven't found any official statements one way
or another about cross-version compatibility and support.

Does anyone know for sure?  Can anyone point me to some official
docs?

Thanks,

Liz