Michael Dolan Dot Com

Thursday, May 31st, 2007

GPLv3 Final Call (and RMS’ commentary on why upgrade from GPLv2)

New draft of GPLv3 is available here - Final Call.  It’s good to see Apache license compatibility included in the new draft.

RMS’ own commentary on why upgrade is available below (also explains license incompatibility and what that means with regard to GPLv2) can be found at the URL below.

http://gplv3.fsf.org/rms-why.html

Why Upgrade to GPL Version 3
by Richard Stallman

Version 3 of the GNU General Public License will soon be finished, enabling free software packages to upgrade from GPL version 2. This article explains why upgrading the license is important.

First of all, it is important to note that upgrading is a choice. GPL version 2 will remain a valid license, and no disaster will happen if some programs remain under GPLv2 while others advance to GPLv3. These two licenses are incompatible, but that isn’t a serious problem.

When we say that GPLv2 and GPLv3 are incompatible, it means there is no legal way to combine code under GPLv2 with code under GPLv3 in a single program. This is because both GPLv2 and GPLv3 are copyleft licenses: each of them says, “If you include code under this license in a larger program, the larger program must be under this license too.” There is no way to make them compatible. We could add a GPLv2-compatibility clause to GPLv3, but it wouldn’t do the job, because GPLv2 would need a similar clause.