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Eclipse Public License

The Eclipse Public License (EPL) is a free and open source software license most notably used for the Eclipse IDE and other projects by the Eclipse Foundation. It replaces the Common Public License (CPL) and removes certain terms relating to litigations related to patents. The Eclipse Public License is designed to be a business-friendly free software license, and features weaker copyleft provisions than licenses such as the GNU General Public License (GPL).The receiver of EPL-licensed programs can use, modify, copy and distribute the work and modified versions, in some cases being obligated to release their own changes.

The EPL is listed as a free software license by the Free Software Foundation (FSF) and approved by the Open Source Initiative (OSI). Discussion of a new version of the EPL began in May 2013. Version 2.0 was announced on 24 August 2017. On January 20, 2021, the license steward for the license was changed from Eclipse.org Foundation, Inc. to Eclipse Foundation AISBL (Brussels, Belgium).

Compatibility

The EPL 1.0 is not compatible with the GPL, and a work created by combining a work licensed under the GPL with a work licensed under the EPL cannot be lawfully distributed. The GPL requires that "[any distributed work] that ... contains or is derived from the [GPL-licensed] Program ... be licensed as a whole ... under the terms of [the GPL]", and that the distributor not "impose any further restrictions on the recipients' exercise of the rights granted". The EPL, however, requires that anyone distributing the work grant every recipient a license to any patents that they might hold that cover the modifications they have made. Because this is a "further restriction" on the recipients, distribution of such a combined work does not satisfy the GPL.

The EPL, in addition, does not contain a patent retaliation clause.

Latest version of the EPL

Version 2.0 is the latest version of the Eclipse Public License.

Version 2.0

Version 2.0 of the Eclipse Public License was announced on 24 August 2017. The Eclipse Foundation maintains an FAQ.The FSF has analyzed the license in relation to GPL license compatibility and added it to their official list. The bare license notice is available in several formats, including plain text. In terms of GPL compatibility, the new license allows the initial contributor to a new project to opt in to a secondary license that provides explicit compatibility with the GNU General Public License version 2.0, or any later version. If this optional designation is absent, then the Eclipse license remains source incompatible with the GPL.

Other changes include:

  • the license now applies to "files" not "modules"
  • the new license is international because the choice of law provision has been removed
  • the new license is suitable for scripting languages, including JavaScript

The Eclipse Foundation advises that version 1.0 is deprecated and that projects should migrate to version 2.0. Relicensing is a straightforward matter and does not require the consent of all contributors, past and present. Rather, the version 1.0 license allows a project to adopt any new version by simply updating the relevant file headers and license notices.

EPL considered as copyleft license

The EPL is considered a weak copyleft license.Weak copyleft licenses requires you to disclose your source on source code, but not on binaries and therefore you can compile covered sources with others and distribute the resulting (merged) binaries under the license of your choice. With ‘strong’ copyleft license, the GPL family, you are obligated to reuse the same license in case of re-distribution of copies or derivatives on both source and binaries.\

Terms and Conditions of EPL

The EPL license is a copyleft license. If you modify an EPL’ed component and distribute it in the source code form as part of your program, you’re required to disclose the modified code under the EPL. If you distribute such a program in its object code form, you’re required to state that the source code can be made available to the recipient upon request. You’re also required to share the method for requesting the source code.

The Eclipse Foundation makes clear that, in their opinion, ‘merely interfacing or interoperating’ with an Eclipse plugin does not make your code a derivative work of the plugin.

If you redistribute a program with an EPL component, you are obligated to include the full license text and the copyrights.

The EPL protects the author from possible lawsuits or damages caused if a company used his/her component in a commercial product. It also offers patent grant.