GPLv2 to v3 upgrade and "further restrictions" issue

[Janez Pers]

Roberto Gordo Saez wrote:
> Hello, I want to upgrade a program from GPLv2 to GPLv3, and I am quite
> confused because some special conditions attached to the GPL in this
> particular program. I need your help to understand this.
> 
> I'm *not* the copyright holder. The program is under GPLv2 "or (at your
> option) any later version", with an additional restriction: usage for
> commercial products is not allowed.

As far I understand, such license is NOT GPL V2 compliant. I would
avoid it. At least, its licensing is conflicting.

GPL does not prohibit commercial use, it encourages it, and whoever
is the copyright holder he may have some murky intentions with it.

I am not a layer and this is only personal opinion, but the license
may be interpreted in the way that you choose GPLV3 (author gives you
this option), then follow the letter of GPLV3 and strip off the
special restrictions.

In step three you might get angry email from the copyright holder and a 
threat with a lawsuit, and then you are on your own :)

I would avoid it alltogether.