MPL-1.1 vs. MPL-2.0

Attribute	MPL-1.1	MPL-2.0
License Version	1.1	2.0
Scope	Software	Software
Compatibility	GPL-compatible	GPL-compatible
Patent Grant	No explicit patent grant	Explicit patent grant
Attribution	Required	Required

Introduction

The Mozilla Public License (MPL) is a free and open-source software license developed and maintained by the Mozilla Foundation. It is designed to be a flexible and permissive license that allows developers to use, modify, and distribute software while ensuring that the original source code remains open and accessible. The MPL has gone through several versions over the years, with MPL-1.1 and MPL-2.0 being two of the most widely used versions. In this article, we will compare the attributes of MPL-1.1 and MPL-2.0 to help developers understand the differences between the two licenses.

Scope of Coverage

One of the key differences between MPL-1.1 and MPL-2.0 is the scope of coverage provided by each license. MPL-1.1 is a copyleft license that requires any modifications or derivative works of the original software to be distributed under the same license terms. This means that developers who use software licensed under MPL-1.1 must also make their source code available to others. On the other hand, MPL-2.0 is a weak copyleft license that only requires modifications to the original code to be made available under the MPL-2.0 license. This gives developers more flexibility in how they license their modifications while still ensuring that the original source code remains open.

Compatibility with Other Licenses

Another important factor to consider when choosing between MPL-1.1 and MPL-2.0 is their compatibility with other open-source licenses. MPL-1.1 is known for its strict compatibility requirements, as it is not compatible with some popular licenses such as the GNU General Public License (GPL). This can make it difficult for developers to combine code from projects with different licenses. On the other hand, MPL-2.0 was designed to be more compatible with other open-source licenses, including the GPL. This makes it easier for developers to incorporate code from different projects without running into licensing conflicts.

Patent Protection

One of the key improvements in MPL-2.0 compared to MPL-1.1 is the inclusion of stronger patent protection provisions. MPL-2.0 includes a patent retaliation clause that grants a license to any patents that are necessary to implement the software covered by the license. This helps protect developers and users from patent lawsuits related to the software. In contrast, MPL-1.1 does not include explicit patent protection provisions, which can leave developers vulnerable to patent litigation. This makes MPL-2.0 a more attractive option for projects that may be subject to patent disputes.

Termination and Reinstatement

Another important aspect to consider when comparing MPL-1.1 and MPL-2.0 is the termination and reinstatement provisions of each license. MPL-1.1 includes a termination clause that allows the license to be revoked if the licensee fails to comply with the terms of the license. Once the license is terminated, the licensee must stop using and distributing the software. However, MPL-1.1 also includes a reinstatement clause that allows the licensee to regain the license if they come back into compliance with the terms. In contrast, MPL-2.0 does not include a termination clause, which means that the license cannot be revoked once it has been granted.

Community Feedback and Adoption

Both MPL-1.1 and MPL-2.0 have been widely adopted by the open-source community, but MPL-2.0 has received more positive feedback from developers and organizations. The improvements in MPL-2.0, such as stronger patent protection and better compatibility with other licenses, have made it a more attractive option for many projects. As a result, more projects are choosing to use MPL-2.0 over MPL-1.1. This trend is likely to continue as developers become more aware of the benefits of MPL-2.0 compared to MPL-1.1.

Conclusion

In conclusion, both MPL-1.1 and MPL-2.0 are valuable open-source licenses that provide developers with the freedom to use, modify, and distribute software while ensuring that the original source code remains open. However, there are key differences between the two licenses that developers should consider when choosing which license to use for their projects. MPL-1.1 is a strict copyleft license with limited compatibility with other licenses, while MPL-2.0 is a weak copyleft license with stronger patent protection and better compatibility. Ultimately, the choice between MPL-1.1 and MPL-2.0 will depend on the specific needs and goals of each project.