those aguments aside to answer your question. If you paid the upgrade price for P5 then legaly you cannot giveaway or sell your P4 as an upgrade is not legally a full version (even though you need no P4 code to run it)your copy of P5 is considered an extention of your P4 license. If you bought the full version OTOH, then you can get a license transfer from CL for your copy of P4.