Previous use license request: running software that is more than 3 versions back

http://usa.autodesk.com/getdoc/id=GS17292981

When you append the older code to the to the current license file and you parse the license file, it will look like this:

There is no need to request the entire license file on the SAME date because AutoCAD 2009 is looking for the Feature Code:  57600ACD_2009_0F.

Because we would like you to stay current, the older licenses are typically generated for the duration of 1 year from date of request.