The Apache License is
permissive; unlike
copyleft licenses, it does not require a
derivative work of the software, or modifications to the original, to be distributed using the same license. It still requires application of the same license to all unmodified parts. In every licensed file, original copyright, patent, trademark, and attribution notices must be preserved (excluding notices that do not pertain to any part of the derivative works). In every licensed file changed, a notification must be added stating that changes have been made to that file. If a NOTICE text file is included as part of the distribution of the original work, then derivative works must include a readable copy of these notices within a NOTICE text file distributed as part of the derivative works, within the source form or documentation, or within a display generated by the derivative works (wherever such third-party notices normally appear). The contents of the NOTICE file do not modify the license, as they are for informational purposes only, and adding more attribution notices as addenda to the NOTICE text is permissible, provided that these notices cannot be understood as modifying the license. Modifications may have appropriate copyright notices, and may provide different license terms for the modifications. Unless explicitly stated otherwise, any contributions submitted by a licensee to a licensor will be under the terms of the license without any terms and conditions, but this does not preclude any separate agreements with the licensor regarding these contributions.
Apache License 2.0 The Apache License 2.0 attempts to forestall potential patent litigation in Section 3. The user is granted a patent license from each contributor to "make, have made, use, offer to sell, sell, import, and otherwise transfer the Work." Through an
in terrorem clause, if the user sues anyone alleging that the software or a contribution within it constitutes patent infringement, any such patent licenses for that work are terminated. ==Compatibility==