The Eclipse Public License (EPL) provides specific guidelines for how modifications to the software are to be handled. Under the EPL, if you modify the source code of EPL-licensed software, you are required to make your modified version available under the same license. This means if you create a derivative work, you must also distribute it under the EPL when sharing it with others. This ensures that the freedoms granted by the EPL are preserved in your modified version, promoting continued openness in the software ecosystem.
However, the EPL includes a unique provision that addresses how modifications are treated when it comes to integrating with other software. If you develop a modified version and use it in conjunction with software that is not licensed under the EPL, you may not need to license your entire project under the EPL as long as you only distribute the modified EPL components separately. This allows developers the flexibility to combine EPL-licensed software with other software licenses without the obligation to open-source their entire application. For example, if you add functionality to an EPL-licensed library but integrate it with a proprietary application, you can keep that proprietary application closed while still sharing your improvements to the library itself.
In summary, the EPL promotes collaboration by requiring that modifications to its source code remain open under the same license while also offering flexibility for developers working on broader projects. By balancing open-source principles with practical usage scenarios, the EPL allows developers to contribute to open-source projects without imposing overly stringent restrictions on their own software development practices. This makes the EPL an appealing choice for developers looking to ensure both compliance and innovation in their projects.