[Owncloud] Can third party apps be closed source?

[Muljadi Budiman]

Hi.

Have been trying to get an answer to this, can't find anything relevant in the mailing list in the past 3 months and none of the readme in the code seem to say anything, and none of the current existing apps are closed source, so…

If I deploy Owncloud to a private web server (but does serve outside to the public), and I make third party apps for it, can I keep the third party app closed source?  I understand that if my third party app need special functionality and I have to add new APIs to the Owncloud core, I have to release the core changes.  But do I need to make the third party apps source be available?

Thanks.
Muljadi Budiman.