Dark Frontier Free will be removed from Apple Store, but the Premium version, "Dark Frontier", will still live on the Apple Store.
Link for the Dark Frontier Free game:
https://itunes.apple.com/us/app/id700748451?mt=8a
But not all is sad news. A new update is coming soon, bringing new levels, enemies, bosses, heroes and traps. Also it gonna include localization to Russian and Portuguese.
Keep your eyes open for the news!