upstream changing from GPL-2+ to GPL-3+ without copyright holders permission

[Eriberto Mota <eriberto@debian.org>]

Hi folks,

I have a basic doubt.

A program called "test" was released by Bob over GPL-2+. This program
got contributions from Ana and Chloe. The development was stopped some
years later and, now, Ted want continue this development. However, Ted
kept the name "test" and changed the licensing to GPL-3+ without a
permission from previous copyright holders, that are inactive. Is
possible do it, only considering the plus signal in previous licensing
(GPL-2+)?

Regards,

Eriberto