Do I have to release my customized open source code?
If I use open source software and make changes to it, am I required to release the code?
This will depend on which open source license the software has been released under. If it's the GPL, which is common, then you are required to make your modified source code available only if you distribute the code. If anyone outside of your organization runs the software, then that is considered distribution. If the software will remain internal, then you are not required to release the code.
Even if you are not required by the license to release the source code for your modifications, it is very likely in your best interest to do so. By giving your improvements to the community, you reduce the burden on your organization to maintain a separate version.
From the editor: Find more about the legal requirements involved in using open source software in this response from attorney Scott Nathan.
This was first published in September 2005