I licensed an iOS project under MIT license and a friend made one contribution, adding a few lines to the README.md. The project has been forked twice.

I would like to make the second version closed source. This answer suggests that in order to do so, I would need the contributor to agree. If so, what form would this agreement need to take? Would verbal agreement or an email be ok or can I just update the licence on my repo and make it private as Martijn's answer seems to suggest? I realise that the original code can still be used under the MIT license so someone coming across the forked code could use that.

To sum up, can I just switch my project to private (and update the license) otherwise which steps must I take to get the agreement of my one contributor, make the repo private and any further versions closed source?

UPDATE: I just came across this answer that seems to suggest I can just make my repo private.

  • @MadHatter - Thanks, that answers my question - YES I can just made it private – Dave Chambers Aug 29 '18 at 10:36
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    The contribution you linked to is quite trivial. Even if you couldn't accept this contribution (you had to remove it), it would be quite trivial to rewrite it in your own words (there are only so many ways to inform a user that he has to issue the 'pod install' command first). – Brandin Aug 29 '18 at 10:41
  • @Brandin Agreed. And in fact since the app is now going to be closed source and private on Github, nobody except me will read the README anyway! – Dave Chambers Aug 29 '18 at 10:43
  • @DaveChambers glad you felt you got your question answered! How do you want to handle this, so the question doesn't float around forever? Delete your question? Flag it for moderator closure as a duplicate? I could write a short answer for acceptance, but it feels a bit like cheating. +1 from me, by the way, since you did your own research! – MadHatter Aug 29 '18 at 10:56
  • @MadHatter I accepted the closure as a dup. Cheers – Dave Chambers Aug 29 '18 at 11:04