Open Sky Public License (OSPL)
Simple & Convenient
The OSPL is a modified version of the Mozilla Public License (MPL) used for Netscape, Firefox, Thunderbird, and many other applications. The license is the result of a large community of developers and lawyers coming together to design a flexible license that satisfies everyone - including end-users, programmers, open source advocates, and legal scholars. More detailed information on the OSPL (and MPL) is contained below.
The Open Sky Public License is available here in plain text.
What changes did Open Sky make to the MPL?
Not many. Open Sky simply replaced all references to Netscape or Mozilla with Open Sky and added an additional exhibit to protect the Open Sky brand (logos, trademarks, etc).
What am I allowed to do with OSPL code?
The OSPL is a very convenient license that allows you to run the software, fix any bugs, distribute the software, build new software modules as add-ons, and potentially sell any new modules you develop.
What am I not allowed to do with OSPL code?
You may not sell outright any OSPL code or any derived works of the code. You may distribute binary copies under an additional license provided it does not interfere with the OSPL. If you make modifications to OSPL code and you distribute those modifications - then you must make those modifications available to everyone using that OSPL code (commonly known as a reciprocity obligation).
Why do you use the OSPL?
Open Sky uses the OSPL for three primary reasons: (1) to insure no single client obtains a lock on Open Sky's core intellectual property and techniques, (2) to allow clients to freely obtain Open Sky source code and modify that code without Open Sky's help and without potentially threatening Open Sky or other clients of Open Sky, and (3) to insure the highest quality code for all clients.