Here the term “compatibility” refers to the two following conditions:

1. When a software developer makes use of more than one external module in the development of a single project, and when the licenses of used modules do not conflict with each other, we say these licenses are compatible with each other.

2. When a software developer modifies a given program, and the modified part makes use of other modules; when the licenses of the modules do not conflict with the license of the modified program, we say the licenses are compatible with each other.

The following is a detailed discussion for the compatibility of the free/open source software licenses listed on OpenFoundry: