"This is it. After a year and a half of debate and derision, the
final last-call draft of the cornerstone open source GNU General
Public License (GPL) version 3 is out for discussion.
The biggest change in the fourth and likely final draft of the
GPL version 3 is that the new license will be compatible with the
Apache 2.0 open source license, which is widely deployed and
extremely popular. Though GPL version 3 will be compatible with
Apache, the new GPL will not be compatible with GPL version 2.
"'First of all, it is important to note that upgrading is a
choice,' Richard Stallman, founder of the Free Software Foundation,
wrote in an essay published today about the GPL version 3. '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