When will Esperanto be available for the ios app?
I'm not sure anyone can say for sure, but so far, it seems to have taken a few months for new courses to make it to the mobile apps. Keep in mind all three platforms are treated differently, so it may come first to Android, then iOS then Windows phone, in a matter of a few weeks/months (I said that in a completely random order, just as an example).
Alternatively, if you want to do the course on your phone/tablet, you can do it right now through the mobile version of the website, accessed through your browser. It doesn't have an offline mode and some other features specific to the app, but has other features specific to the website.