GPLv2 vs. MPL 2.0

Attribute	GPLv2	MPL 2.0
License Type	Copyleft	Weak Copyleft
Compatibility with other licenses	Less compatible	More compatible
Derived works	Must be under GPLv2	Can be under different license
Patent Grant	No explicit patent grant	Explicit patent grant
Attribution	Required	Required

Introduction

When it comes to open source licenses, two popular choices are the GNU General Public License version 2 (GPLv2) and the Mozilla Public License version 2.0 (MPL 2.0). Both licenses have their own unique attributes and are widely used in the open source community. In this article, we will compare the key features of GPLv2 and MPL 2.0 to help you understand the differences between them.

License Scope

One of the main differences between GPLv2 and MPL 2.0 is their scope. GPLv2 is a copyleft license, which means that any derivative works must also be licensed under the GPLv2 or a compatible license. This ensures that the source code remains open and freely available to the community. On the other hand, MPL 2.0 is a weak copyleft license, which allows developers to combine MPL-licensed code with code under other licenses without requiring the entire project to be open source.

Compatibility

Another important factor to consider when choosing a license is compatibility with other licenses. GPLv2 is not compatible with proprietary licenses, as it requires derivative works to be open source. This can be a limitation for developers who want to use GPLv2-licensed code in proprietary projects. In contrast, MPL 2.0 is more flexible and allows developers to combine MPL-licensed code with code under different licenses, including proprietary licenses.

Distribution Requirements

One key aspect of open source licenses is the distribution requirements they impose on developers. GPLv2 requires that the source code of any modified versions of the software be made available to users under the same license. This ensures that users have access to the source code and can modify it as they see fit. On the other hand, MPL 2.0 only requires the distribution of the source code for the MPL-licensed files, allowing developers to keep the rest of their code proprietary.

Patent Grants

Patent grants are another important consideration when choosing a license. GPLv2 does not include explicit patent grants, which means that developers may need to negotiate separate patent licenses with contributors. This can be a complex and time-consuming process, especially for projects with multiple contributors. In contrast, MPL 2.0 includes a patent grant that provides protection to both contributors and users of the software, making it easier to use MPL-licensed code in commercial projects.

Termination

One area where GPLv2 and MPL 2.0 differ is in their termination clauses. GPLv2 includes an automatic termination clause that revokes the license if the licensee violates its terms. This can be a harsh penalty for unintentional violations and may lead to legal disputes. On the other hand, MPL 2.0 does not include an automatic termination clause, giving developers more flexibility in resolving license violations without resorting to legal action.

Community Impact

Finally, it is important to consider the impact of a license on the open source community. GPLv2 has been widely adopted by the open source community and is considered a strong copyleft license that promotes the sharing of code. However, some developers may find its strict requirements too restrictive for their projects. In contrast, MPL 2.0 is a more permissive license that allows developers to combine MPL-licensed code with proprietary code, making it a popular choice for commercial projects.