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This document is to help Apache developers understand what they need to do to apply the Apache License, Version 2.0 or ALv2 to Apache software, including source code, documentation, and binary distributions. It is descriptive guidance, and does not supplant or otherwise modify any of the terms within the license itself. In case of uncertainty, consult general Apache policy.

Information on other Apache-related licenses and updates regarding compatibility with other open source licenses appears in the Licenses section.


Understanding the 2.0 license

The ALv2 is this set of self-documented copyright and patent licensing terms. Anyone can use the license, not just the ASF and its projects, and can be applied by reference to the versioned license terms. An appendix to the license describes how to do this.

Note that the ASF does not use copyright assignment and that the original authors retain the copyrights for individual parts of the collective work . The method described in the appendix is only suitable for copyright owners, so the ASF uses a variation of this method.

Section 4d of the license provides for attribution notices to be included with a work in a NOTICE file, so the attribution notices remains, in some form, within any derivative works. Apache projects must include correct NOTICE documents in every distribution.

Applying the license to new software

To apply the ALv2 to a new software distribution, include one copy of the license text by copying the contents of LICENSE-2.0.txt into a file called LICENSE in the top directory of your distribution. If the distribution is a jar or tar file, try to add the LICENSE file first in order to place it at the top of the archive. This covers the collective licensing for the distribution.

In addition, you must include a correct NOTICE file in the same directory as the LICENSE file.

Each original source document (code and documentation, but not the LICENSE and NOTICE files) should include a short license header at the top. If the distribution contains documents not covered by an ICLA, CCLA or Software Grant (such as third-party libraries), consult the policy guide.

Updating existing software

In brief, the aim is to achieve a final distribution as described above in applying the license to new software. Some conversion tools are listed here.

Frequently asked questions about updates

Do I have to convert Apache licenses in source code from 1.1 to 2.0?

If the Apache Software Foundation owns and distributes the code, then Yes. All software distributions were to be converted to the new license by March 1, 2004.

If the ASF does not own the code, the decision is up to the copyright owner. Naturally, we strongly recommend that you upgrade to the new license.

Do I have to convert old versions and branches of code to the new license?

Only if you want the ASF to make a new release of that code. "Dead" branches of code do not have to be updated.

Other frequently asked questions

Where can I find more information?

Start with the legal affairs home page.

Where do I find a copy of the new license?

Do I have to have a copy of the license in each source file?

You only need to add one full copy of the license per distribution. See the policy.

In my current source files I have attribution notices for other works. Do I put this in each source file now?

See the policy.

No. Though committers retain copyright, Apache asks that they do not add copyright statements. See the policy for more details.

Can we call the LICENSE and NOTICE files LICENSE.txt and NOTICE.txt?

You can do this, however we prefer that you call the files LICENSE and NOTICE.

Should we include the license in source files for documentation (e.g. XML that transforms to HTML)?

Yes. See the policy for more details.