Releasing Software Under Multiple Licenses

Question

[Bio_X2Y]

If I release a piece of bioinformatics software under a certain license, e.g. LGPL, can I later decide to release parts or all of that software under a completely different license as part of another product, e.g. GPL? (leaving the original product and terms unaffected of course)

To distil the question to its most general form, is dual-licensing always possible, or can some licenses prevent the owner from re-releasing under different license(s)?

Thanks

Answer 1

[Michael Schubert]

When your are the copyright holder, it is always possible to release your work under any license you want (as long as the license itself is permitted by law).

Also, when you are moving from a restricted to a liberal license there are no issues involved. When you are moving from a liberal to a restrictive license, your last liberal release does, technically speaking, not get deprecated and can still be forked under the old license's conditions. So, once you release your work under a specific license, you can not take it back.

License compatibility issues only arise when (a) you are not the copyright holder [see Wikipedia on moving from GNU FDL to CC] or (b) you (or anyone else) wants to release derivative work under a different license.

As always, feel free to correct me (if you have a stronger background in law) and think I'm wrong.

[Joachim]

On top of that, you can have a look at http://en.wikipedia.org/wiki/Multi-licensing and get some examples on 'License compatibility'.

[Bio_X2Y]

Very clear answer, thanks.