From the Realmac blog:
Unfortunately, Ember for iOS has never done as well as we’d like, and simply doesn’t earn enough revenue to pay for a developer to work on it … and will soon be discontinuing the current iOS version.[^-361149314]
I have been using the app for a while and was considering to replace Evernote with it, but not having it on my phone doesn’t make it that useful for me in the long run. While I perfectly well understand the reasoning, it’s sad to see it go.