No.
MS is defining a set of standard APIs that will handle mapping of data between any proprietary formats the camera folks might choose to use in their hardware and the new open raw spec.
The spec is being defined in consultation with the camera vendors (and Adobe) so it will be compatible with all their formats.
MS has a lot of experience in extensible data formats through their Windows Media and MS-DRM efforts, to say nothing of their recent conversion to the religion of Xml. :-)
So, fear not; the spec will be doubtlessly updated but likely no more often than every few years and without breaking compatibility.
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