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
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.
And the court noted that no damage was done to the copyright holder by
someone else modifying their own copy of a work.