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Contributions to the ICU library

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Why Contribute?

ICU is an open source library that is a de-facto industry standard for internationalization libraries. Our goal is to provide top of the line i18n support on all widely used platforms. By contributing your code to the ICU library, you will get the benefit of continuing improvement by the ICU team and the community, as well as testing and multi-platform portability. In addition, it saves you from having to re-merge your own additions into ICU each time you upgrade to a new ICU release.

Current Process



Legal Issues ICU 1.8.1-57

The following process was in place up to ICU 57, when the old ICU license was used.

Old Process

In order for your code to be contributed, you need to assign to IBM joint copyright ownership in the contribution. You retain joint ownership in the contribution without restriction. (For the complete set of terms, please see the forms mentioned below.)

The sections below describe two processes, for one-time and ongoing contributors. In either case, please complete the form(s) electronically and send it/them to IBM for review. After review by IBM, please print and sign the form(s), send it/them by mail, and send the code. The code will then be evaluated.

Please consult a legal representative if you do not understand the implications of the copyright assignment.

One-Time Contributors

If you would like to make a contribution only once or infrequently, please use the Joint Copyright Assignment - One-time Contribution form. ( The contribution will be identified by a bug ID which is unique to the contribution and entered into the form. Therefore, please make sure that there is an appropriate bug (or Request For Enhancement) in the ICU bug database, or submit one.

The code contribution will be checked into a special part of the ICU source code repository and evaluated. The ICU team may request updates, for example for better conformance with the ICU design principles, coding and testing guidelines, or performance. (See also the Requirements (§) above.) Such updates can be contributed without exchanging another form: An ICU team member commits related materials into the ICU source code repository using the same bug ID that was entered into the copyright assignment form.

Ongoing Contributors

If you are interested in making frequent contributions to ICU, then the ICU Project Management Committee may agree to invite you as an ongoing contributor. Ongoing contributors may be individuals but are more typically expected to be companies with one or more people (“authors”) writing different parts of one or more contributions.

In this case, the relationship between the contributor and the ICU team is much closer: One or more authors belonging to the contributor will have commit access to the ICU source code repository. With this direct access come additional responsibilities including an understanding that the contributor will work to follow the technical Requirements (§) above for contributions, and agreement to adhere to the terms of the copyright assignment forms for all future contributions.

The process for ongoing contributors involves two types of forms: Initially, and only once, an ongoing contributor submits a Joint Copyright Assignment by Ongoing Contributor form, agreeing to essentially the same terms as in the one-time contributor form, for all future contributions. (See the form at

The contributor must also send another form, Addendum to Joint Copyright Assignment by Ongoing Contributor: Authors, for the initial set and each addition of authors to ICU contributions, before any contributions from these authors are committed into the ICU source code repository. (Only new, additional authors need to be listed on each such form.) The contributor agrees to ensure that all of these authors agree to adhere to the terms of the associated Joint Copyright Assignment by Ongoing Contributor Agreement. (See the Authors Addendum form at

Some of an ongoing contributor's authors will have commit access to the ICU source code repository. Their committer IDs need to be established before completing the Authors Addendum form, so that these committer IDs can be entered there. (The committer IDs should be activated only after the form is received.)

Committer authors commit materials directly into the appropriate parts of the ICU source code repository. Contributions from an ongoing contributor are identified by their association with the contributor's committer IDs.

Previous Contributions

All previous “one-off” contributions from non-IBM sources to ICU are listed on the code contributions page in ICU's source code repository. The page contains links to the softcopies of the Joint Copyright Assignment forms. See

In addition, the following non-IBM companies are registered as Ongoing Contributors:

  • Apple
  • Google

See the repository folder that contains the contributions page for the full set of softcopies of contributor agreements including one-off contributions, ongoing-contributor agreements and author-addendum documents to ongoing-contributor agreements: