An important thing to note about the GPLv3 is that it is not just an incremental improvement or modernization of the GPLv2, contrary to its name.
It’s effectively a different license that’s even one level stricter than the GPLv2 in a substantial way.
In addition to the base requirements of the GPLv2 for releasing source code for distributed binaries, it goes one step further and requires that modified binaries can be installed onto the hardware that distributed the original binaries.
Unlike simple release of source code, this has engineering implications for hardware manufacturers. It prevents “locked down” devices and forces devices to be open and reprogrammable. “Tivo-ization” is a term referring to the practice of “locking down” a device, which is often used in discussions around GPLv3.
This is why Linus Torvalds refused to adopt GPLv3 for Linux, because in his view, this was going too far.
So if you’re in the market for a copyleft OSS license, keep in mind that GPLv3 is not automatically the best fit, and should not necessarily be automatically used over GPLv2 just because it’s the newest version in the “GPL series”.
It represents an additional step of strictness on the restrictiveness scale. If you’d like distributors to release source code, but don’t necessarily need them to make their devices openly programmable, GPLv2 is still the license to use.
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