Alexandre Oliva wrote:
or add my own changes to it.No, in order to modify a work you need permission from the copyright holder and, in some jurisdictions, also from the author (in case the author is allowed by law to assign the copyright to other parties while retaining moral rights, one of which is to object to modifications; this may sound alien to US-centered folks, but it's in the Berne convention and implemented in various legislations around the world)
It turns out, "this depends...". You specifically have the right, in the US, at least, to make changes that are "an essential step in the utilization of the computer program". Which turns out to include adding improvements you need.
http://www.techlawjournal.com/topstories/2005/20051107.aspAnd the court noted that no damage was done to the copyright holder by someone else modifying their own copy of a work.
-- Les Mikesell lesmikesell gmail com