In addition to the original (4-clause) license used for BSD, several derivative licenses have emerged that are also commonly referred to as a "BSD license". Today, the typical BSD license is the 3-clause version, which is revised from the original 4-clause version. In all BSD licenses as following, is the year of the copyright. As published in BSD, is "Regents of the University of California".
Previous license Some releases of BSD prior to the adoption of the 4-clause BSD license used a license that is clearly ancestral to the 4-clause BSD license. These releases include some parts of 4.3BSD-Tahoe (1988), about 1000 files, and Net/1 (1989). Although largely replaced by the 4-clause license, this license can be found in 4.3BSD-Reno, Net/2, and 4.4BSD-Alpha.
4-clause license (original "BSD License") The original BSD license contained a clause not found in later licenses, known as the "advertising clause". This clause eventually became controversial, as it required authors of all works deriving from a BSD-licensed work to include an acknowledgment of the original source in all advertising material. This was clause number 3 in the original license text: On January 31, 2012, UC Berkeley Executive Director of the Office of Intellectual Property and Industry Alliances established that licensees and distributors are no longer required to include the acknowledgement within advertising materials. Accordingly, the advertising clause 3 of the original 4-clause BSD license for any and all software officially licensed under a UC Berkeley version of the BSD license, was deleted in its entirety. Other BSD distributions removed the clause, but many similar clauses remain in BSD-derived code from other sources, and unrelated code using a derived license. While the original license is sometimes referred to as the "BSD-old", the resulting 3-clause version is sometimes referred to by "BSD-new." Other names include
new BSD, "revised BSD", "BSD-3", or "3-clause BSD". This version has been
vetted as an Open source license by the
OSI as "The BSD License". though this is not commonly included by other projects. The Free Software Foundation, which refers to the license as the FreeBSD License, states that it is compatible with the GNU GPL. In addition, the FSF encourages users to be specific when referring to the license by name (i.e. not simply referring to it as "a BSD license" or "BSD-style"), as it does with the modified/new BSD license, to avoid confusion with the original BSD license.
0-clause license ("BSD Zero Clause License") The BSD 0-clause license goes further than the 2-clause license by dropping the requirements to include the copyright notice, license text, or disclaimer in either source or binary forms. Doing so forms a
public-domain-equivalent license, the same way as
MIT No Attribution License. It is known as "0BSD", "Zero-Clause BSD", or "Free Public License 1.0.0". Despite its name, it was actually derived from the
ISC license rather than from a previous member of the BSD license family. It was created by Rob Landley and first used in
Toybox when he was disappointed after using the
GNU General Public License in
BusyBox.
Other variations The
SPDX License List contains extra BSD license variations. Examples include: • , a license with only the source code retaining clause, used by Berkeley Software Design in the 1990s, and later used by the
Boost Software License. OSI approved since 2020. • , a variation of BSD-2-Clause with a patent grant. OSI approved since 2017. • , a variation of BSD-3-Clause that adds that a piece of software is not licensed for use in a
nuclear facility. == License compatibility ==