If you own a network license, you can run the current version & 3 versions back. If you need an older version of your Autodesk product, you will need to request a Previous Use License. The instructions are noted here:
NOTE: You can also use the solution above to request older standalone products as well.
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.