When will Hebrew be available to use as a language on the IOS Duolingo app?
See the first entry of the "FAQ" post on top of the "Popular" tab of the "Hebrew from English" forum.
Or this official statement by staff about the delay between the release on the web version and the first release on one of the apps.
I know, right? I too was disappointed to find out that it isn't available yet on the app.
This is a complete guess, but I'm going to say 'when it gets out of beta'?