The GNU General Public License (GPL) is a widely used free software license that guarantees end users the freedom to run, study, share, and modify the software. Over the years, the Free Software Foundation has released various versions, with GPLv2 and GPLv3 being the most prevalent. While both licenses aim to uphold user freedom, they differ in several key areas that reflect evolving technological and legal landscapes.
One of the primary differences between GPLv2 and GPLv3 is their approach to patent rights. GPLv3 includes explicit terms regarding patent licenses, which are designed to prevent contributors from suing users for patent infringement. This addition was largely in response to the growing number of software patent litigations, providing an additional layer of protection for users and developers by ensuring that all users of the software are also granted patent licenses.
Another significant difference is how each license addresses digital rights management (DRM) and “Tivoization.” GPLv3 includes clauses aimed at preventing Tivoization, a practice where hardware manufacturers use cryptographic keys to prevent users from running modified versions of the software on their devices. By prohibiting this practice, GPLv3 ensures that users retain the freedom to modify and run software on any hardware.
GPLv3 also introduces more comprehensive internationalization and compatibility improvements. It incorporates language that is more universally applicable, taking into account the legal systems outside the U.S., and addresses compatibility with other open source licenses more effectively. This change makes it easier for projects under different licenses to collaborate or merge codebases without legal conflicts.
In terms of compliance and enforcement, GPLv3 provides clearer guidelines and mechanisms. For example, it offers a more straightforward cure period for license violations, allowing violators the opportunity to rectify breaches before license termination. This approach emphasizes remediation over punishment, promoting better adherence to the license’s principles.
From an administrative perspective, GPLv3 introduces the concept of an “or later” clause, which allows users to choose to follow either the version of the GPL they received the software under or any later version published by the Free Software Foundation. This clause provides flexibility and future-proofs projects against legal and technological changes.
In summary, while GPLv2 and GPLv3 share the core philosophy of software freedom, GPLv3 addresses modern challenges such as patent issues, DRM, international compatibility, and clearer compliance mechanisms. Organizations and developers choosing between these licenses should consider their specific needs, potential legal environments, and the desired level of freedom and protection for their software and its users.