Dual and Multiple Licensing

The owner of a copyright can license his or her work any number of times. Distributors of proprietary software do that when they grant discounts to favored customers, issue blanket licenses for unlimited copies to large corporations, and apply shrink-wrap licenses to copies sold in stores.

The MPL license described in Chapter 7 offered one example of dual licensing. Under the MPL, the Initial Developer may designate portions of the Covered Code as Multiple-Licensed. This allows any licensee to choose to accept those portions under the MPL or a second license specified in "Exhibit A." Where that option is used, Initial Developers often choose the GPL.

More sophisticated examples than this of dual and multiple licensing are now widely used for important software. The owners of copyrights in open source software may simultaneously license that same software under non “ open source licenses. This is particularly attractive for licensees who are reluctant to accept certain conditions of the available open source licenses and who are willing to pay extra license fees to relieve themselves of those conditions.

Such software, as originally licensed, is open source. It is available under an open source license. But it is also available under other licenses.

Consider the MySQL data base, which is distributed under the GPL and also under a separate commercial license. MySQL software is often incorporated into larger packages. Depending upon how the GPL is interpreted, such larger packages may become subject to the reciprocity condition of the GPL. This is unacceptable to some potential customers of MySQL who want to keep their derivative works proprietary.

The distributor of MySQL is also the owner of the copyrights in the software. It is thus free to license MySQL simultaneously under as many different licenses as it wants. In addition to the GPL, MySQL offers commercial licenses without reciprocity obligations ”for a fee.

M rten Mickos, the CEO of MySQL, describes his company's dual licensing commercial model this way:

Our paying customers get what they pay for: a commercially supported product with a level of assurance from the vendor and without any typical open source requirement that linked software must be open sourced as well.... Dual licensing allows companies to build viable long- term businesses while at the same time accommodating the needs of the open source/free software community. (See www.mysql.com.)

Mickos explains the quid pro quo of this dual licensing bargain. He points out that their commercial customers benefit from the open source customers because open source software is inherently more reliable and effective. (He calls it " rigorous 'battle-testing.'") Meanwhile, their open source customers benefit from the commercial customers because the MySQL company "can afford to develop and improve the product at a fast pace."

One problem with this model is that contributions made by third parties to MySQL's GPL version must themselves be licensed under the GPL. (See GPL section 2[b].) The owners of the copyrights in the improvements may authorize dual licensing of their contributions under MySQL's commercial licenses, but nothing in the GPL requires them to do so. MySQL can try to avoid this problem by requesting that contributors assign their copyrights to the company, or by expressly accepting contributions under a license that permits MySQL to use the contributions as it sees fit.

Such dual licensing alternatives may have uses other than to avoid reciprocity obligations. Other conditions in an open source license may be unacceptable to prospective licensees. Some companies object to patent termination clauses (e.g., MPL section 8.2, CPL section 7, OSL/AFL section 10.) Some companies seek more elaborate warranties or forms of indemnification than are usually available under open source licenses. Licenses containing special waivers or additional benefits can sometimes be negotiated.

Any prospective licensee dealing with an unacceptable open source license should contact the licensor for other available licensing alternatives. Any licensor of open source software should consider dual licensing options as a way of attracting new customers.