[petek]

I was afraid that might be the case - now that I think of it I think I saw something similar in v5.0 with 5.3 files last year. Would be nice if Autodesk would let you do a "save as" to 5.3 for those of us who can't afford to upgrade all our licenses.

This will make it a lot harder to do adaptive designs and assemblies, with just one seat that can open all the files. It looks like most of the parts carried over from last year are in an older version, anyway.