RS Logix 500 save

I have version 6.20. Recently I made some small changes to a to a new machine with a SLC500. When I went to save the revised program the upload took forever and stalled. I was told this problem had something to do with the revision number. New versions cannot be saved to old versions.
Does anyone know if this is factual? We have all the correct licenses but not all of our machines have been upgraded (they are all over the world). Short of sending all laptops back home is there a quick fix?
Thanks

There is a file conversion problem between "space A" and "space B" data table entries when transfering between version 6.20 and 6.30/7.0 and higher if the file was first made/edited with version 6.3 or higher.

Rockwell advises using the save as function to rename the file when making edits with 6.20 and lower.

Do you mean save as 6.2 when programing with 6.3?

Here is a technote:
http://domino.automation.rockwell.com/applications/kb/RAKB.nsf/0/6357672BA031621D8525708400702A9E?OpenDocument