I believe they only add them to the apps when they are nearly ready to come out of beta.
Oh I see! Thanks Psionpete! That explains :)
not "nearly out of beta" actually, but after a bit of stabilization. it will probably take a few weeks
Yes, you have to wait for an updated app to be released. I did see on the DL FB page a while back that Turkish was "coming soon" to the mobile app.