BSD-4-Clause Guide

The BSD-4-Clause license, also called the BSD “Original” or “Old” License, is the original form of the BSD license. Although it does not require disclosure of source code, it includes an advertising clause that makes its use problematic.

SPDX Identifier: BSD-4-Clause

License Statement in Source Code

Open source under the BSD-4-Clause license generally carries the following statement at the top of the source code.

Copyright (c) <year>, <copyright holder>
All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
 
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. All advertising materials mentioning features or use of this software
must display the following acknowledgement:
This product includes software developed by the <organization>.
4. Neither the name of the <organization> nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
 
THIS SOFTWARE IS PROVIDED BY <COPYRIGHT HOLDER> ''AS IS'' AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Obligations by Use Case

Case 1. Redistribution in Source Form

When redistributing open source under the BSD-4-Clause license in source form, observe the following.

1-1 Notice Obligation

  • Copyright notice
  • Provide a copy of the license
  • Warranty disclaimer notice
  • Include the following statement in all advertising that mentions features or use of the BSD-4-Clause open source
    “This product includes software developed by the <organization>."

In other words, keep the copyright, license, and so on within the source code intact.

Case 2. Redistribution in Binary Form

When building open source under the BSD-4-Clause license and redistributing it in binary form only, observe the following.

2-1 Notice Obligation

  • Copyright notice
  • Provide a copy of the license
  • Warranty disclaimer notice
  • Include the following statement in all advertising that mentions features or use of the BSD-4-Clause open source
    “This product includes software developed by the <organization>."

Generate an open source notice containing the above and enclose it when redistributing the binary.

License Compatibility

Due to the advertising clause, BSD-4-Clause has compatibility issues with other licenses.

Compatibility with Major Licenses

License to CombineCompatibleRemarks
MITCompatibleThe advertising clause must be retained
Apache-2.0CompatibleThe advertising clause must be retained
GPL-2.0/3.0IncompatibleThe advertising clause conflicts with GPL
ProprietaryCompatibleThe advertising clause must be complied with

References