Purchasing a license for 17 gives you the right to use any old version that you want (if you can get the software and your machine still runs it).
I think that as you already have version 6.5 EDU this will run as commercial version as soon as you plug in a licence key (It would have to be a WIBU-key as 6.5 won't run with a Codemeter key as far as I know).
I don't know if you can buy a new license with a WIBU key though - I think it is all Codemeter now.
You might find someone willing to sell an old license (cheaply?) but I believe technically you will never own it as the license is not transferable from one person to another.
Some Archicad distributers used to offer a transfer for a fee but I am not sure if this is still done or not.
The fee is probably close to buying a full license anyway by the time you add it to what you pay for the old license.
Not sure if that has been of any help.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
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