Login  |  繁體中文
感謝您對「自由軟體鑄造場」的支持與愛護,十多年來「自由軟體鑄造場」受中央研究院支持,並在資訊科學研究所以及資訊科技創新研究中心執行,現已完成階段性的任務。 本網站預計持續維運至 2021年底,網站內容基本上不會再更動。
也紀念我們永遠的朋友 李士傑先生(Shih-Chieh Ilya Li)。
Licenses Mozilla Public License 1.1 (MPL)

Open Source Software license

We provide Open Source Software license and legal materials via this page.


Mozilla Public License 1.1 (MPL)

I. Overview

The MPL was developed by Netscape in 1998 for its free/open source Internet browser project – Mozilla. As a business entity, Netscape has taken into many considerations when forming its licensing policy, and has created a very comprehensive licensing structure for the MPL. As a result, the MPL has later become a model license for many other licenses. 


II. Curret Status

At present, the following well-known programs have all chosen the MPL as their licenses: Mozilla Firefox, Bugzilla, Mozilla Thunderbird, Compiere, Zimbra Collaboration Suite and SugarCRM, etc. There are around 300 projects on Freshmeat that have employed the MPL (https://freshmeat.net/browse/14/). Compared with other OSI (Open Source Initiative) licenses, the MPL is ranked as roughly the 7th commonly used OSI license.   

III.Rights and Duties

  1. Rights

There are two kinds of licensers in the MPL: the initial copyright holder of the program, and the contributor of the program. The licensers of the MPL grant all the intellectual property rights except for the trademarks, provided that those intellectual property rights are legally licensable for them. Details of those intellectual property rights licenses are as following:

    (1) Under intellectual property rights (other than patent or trademark): the licensee is granted the right to use, reproduce, modify, display, perform, sublicense and distribute the source code or (part of) the modifications.

    (2) Under patent claims: the licensee is granted the right to make, have made, use, sell, offer for sale, and/or otherwise dispose of the source code or (part of) the modifications. Besides, the licensee has a right to use the original code released by the initial developer.

In addition to the above-mentioned intellectual property rights, the licensee is also free to choose other non-MPL license for the executive version. However, this non-MPL license must not conflict with the MPL, and may not attempt to limit or alter any rights originally granted by the MPL to the program recipients.

The licensee may create a larger work by combining the MPL covered code with other code, even if those codes are not governed by the terms of the MPL. The licensee must, however, make sure the requirements of the MPL are fulfilled.

  2. Duties

When distributing the program, the licensee must fulfill the following requirements:

    (1) Modifications must keep using the MPL;

    (2) Any original version or modifications distributed by the licensee must be made available in source code form to the recipients;

    (3) The licensee must cause all modifications to contain a file documenting the changes he made to create that covered code and the date of any change;

    (4) The licensee may modify the MPL program. Ideally, the licensee should own the intellectual property rights he contributes, or at least is entitled to legally exercise those rights. The reality, however, may not be as expected. In some cases, to make sure the recipients can use the modification legally and without any infringing risks, the licensee must explain the situation and provide supporting information in a text file called “LEGAL.” Information that has to be provided includes the claim and the party making the claim in sufficient detail, so that a recipient will know whom to contact to acquire the license.

    (5) The licensee must duplicate the notice in Exhibit A in each file of the source code. Through the Exhibit A, the recipients should be able to know who the initial developer is, what the licensing terms are, whether it is possible to choose other licenses, and who else are the contributors, etc.

    (6) The licensee must follow the five requirements mentioned above, and include a notice when distributing any executable version, stating that the source code version of the covered code is available as well as information about how to access it.

IV. Other Important Features

  1. Any third parties are free to alter the content of the MPL.

  2. Like the GPL, the MPL requires the modifications keep using the MPL. However, the MPL is more flexible than the GPL, because the initial copyright holder may choose to use specified, non-MPL licenses for some specific source codes. The licensee can make the final decision. For those specific source codes, the licensee is free to choose the MPL, or any other specified non-MPL licenses. 

  3. In a case that the licensee initiate litigation by asserting a patent infringement claim against initial developer or a contributor, the MPL has a dispute resolution procedure for this. Initial developer or a contributor may follow those procedure and ask the licensee to withdraw the litigation claim or pay a royalty, otherwise the copyright and patent license will automatically terminate.

  4. This license shall be governed by California law provisions. With respect to disputes in which at least one party is a citizen of, or an entity chartered or registered to do business in the United States of America, any litigation relating to this license shall be subject to the jurisdiction of the Federal Courts of the Northern District of California.


If a foreigner (Non-American citizen) would like to choose the MPL as his/her license, we would suggest that the governing law provision and the jurisdiction clauses be altered. This is to prevent the worst scenario – should any dispute arises, the licensee will have to go and use the California law and court.

Category: Licenses