The added compatibility comes via the new 1.6 update, which also introduces the ability to seamlessly switch between iPad and iPhone, improved DS performance, the ability to 'insert' GBA games into DS dual-slot, menu button gestures, and improvements to the app's save state features.
In addition to the additions and improvements, version 1.6 also introduces Delta's permanent new logo. The developers were forced to ditch the original logo after Adobe had threatened legal action for its supposed similarities to the Photoshop logo. The new logo isn't drastically different and is still a take on the Greek alphabet character for delta, but the overlapping of the lines should make it different enough to avoid Adobe's wrath.
According to developer Riley Testut, Delta compatibility for Apple TV is also in the works, but there's no word on when this will be introduced at the time of writing.
Delta includes support for NES, SNES, N64, and DS games. Switch support is predictably nowhere to be seen, but this is probably for the best; Nintendo has been on the warpath recently regarding Switch emulators and has filed DMCAs left, right and center to ensure their removal, lending some weight to the idea that the eventual Switch successor may be fully backwards compatible.
