One of the most widely used and most popular free and open source software licences is the  General Public License. I want to know in simple terms: what are the differences between GPL Version 2 and Version 3?Further I found latest Linux-Kernel licensed under GPL V2 not GPL V3 till. What are reasons?
What are the differences between GPL V2 and V3 licenses?
gpl 3;license compatibility;gpl 2;linux kernel
This question was already asked on Stackoverflow in 2008 (but closed as off-topic there). This is a copy of the answer by Will M:Here is a short list of some the major differences:internationalization: they used new terminology, rather than using language tied to US legal conceptspatents: they specifically address patents (including the Microsoft/Novell issue noted in another answer)Tivo-ization: they address the restrictions (like Tivos) in consumer products that take away, though hardware, the ability to  modify the softwareDRM: they address digital rights management (which they call digital restrictions management)compatibility: they addressed compatibility with some other open source licensestermination: they addressed specifically what happens if the license is violated and the cure of violationsI agree with the comment about consulting a lawyer (one who knows  about software license issues, though). In doing these things (and  more), they more than doubled the length of the GPL. GPL 3 is many  things, and one of them is that it is a very complex, technical legal  document.Regarding why the Linux kernel does not adopt version 3, here is a video of Linus Torvalds where he explains his opinion. Some excerpts from his speech:Here we give your version 3 and then we try to sneak in these new rules and try to force everybody to upgrade. That was the part I disliked. And the FSF did some really sneaky stuff. Downright immoral in my opinion.[...]I am thinking tivoization isn't necessarily something that you should strive for. But in my world view it's your decision if you make hardware that blocks down the software. That's your decision as a hardware maker. That has no impact on my a decision as a software maker to give you the software.