LGPL 2 vs. LGPL 3

Attribute	LGPL 2	LGPL 3
License Version	2	3
Compatibility with GPL	Yes	Yes
Patent Grant	No	Yes
Additional Permissions	No	Yes
Relicensing	No	Yes

Introduction

The GNU Lesser General Public License (LGPL) is a widely used open-source software license that allows developers to use, modify, and distribute software while ensuring that the source code remains open and accessible. There are two main versions of the LGPL - version 2 and version 3. In this article, we will compare the attributes of LGPL 2 and LGPL 3 to help developers understand the differences between the two licenses.

Scope of the License

LGPL 2 and LGPL 3 have different scopes when it comes to the software they cover. LGPL 2 is more focused on libraries and allows developers to link their proprietary software with the library without having to release the source code of the proprietary software. On the other hand, LGPL 3 extends the scope to cover any software, not just libraries, and requires that any modifications to the software be released under the same license.

Compatibility with Other Licenses

When it comes to compatibility with other licenses, LGPL 2 and LGPL 3 have some differences. LGPL 2 is compatible with a wider range of licenses, including proprietary licenses, which makes it a popular choice for developers who want to use open-source libraries in their proprietary software. In contrast, LGPL 3 is more restrictive in terms of compatibility and may not be compatible with some proprietary licenses.

Patent Protection

One of the key differences between LGPL 2 and LGPL 3 is the inclusion of patent protection in LGPL 3. LGPL 3 includes a patent clause that aims to prevent patent litigation between contributors and users of the software. This clause is not present in LGPL 2, which means that developers using LGPL 2 may be more vulnerable to patent disputes.

Upstream Compatibility

Another important aspect to consider when choosing between LGPL 2 and LGPL 3 is upstream compatibility. LGPL 2 is not compatible with the GNU General Public License (GPL) version 3, which may limit the ability of developers to combine code from projects licensed under LGPL 2 with projects licensed under GPL 3. On the other hand, LGPL 3 is compatible with GPL 3, which allows for greater flexibility in combining code from different projects.

License Enforcement

When it comes to license enforcement, LGPL 2 and LGPL 3 have different mechanisms in place. LGPL 2 relies on copyright law to enforce compliance with the license terms, while LGPL 3 includes explicit provisions for license enforcement, such as termination clauses for non-compliance. This makes LGPL 3 a more robust license in terms of enforcement compared to LGPL 2.

Conclusion

In conclusion, LGPL 2 and LGPL 3 have some key differences in terms of scope, compatibility, patent protection, upstream compatibility, and license enforcement. Developers should carefully consider these differences when choosing between the two licenses for their projects. While LGPL 2 may be more permissive in some aspects, LGPL 3 offers stronger patent protection and license enforcement mechanisms. Ultimately, the choice between LGPL 2 and LGPL 3 will depend on the specific needs and goals of the project.