Well, to be fair to SkyDemon, it's probably not the SD software that is at fault.
The "Location Services" of the iPad (any version) will not accept a simple NMEA data stream, but only accepts input from external GPSs in some Apple specific format or encoding. To the best of my knowledge, there are only three external devices that supply this specific format. Bad Elf, Garmin Glo and one other. Most of these use BlueTooth as their carrier, but Bad Elf also has a device that plugs into the iPad directly.
Just pairing the iPad with a generic BlueTooth-supporting device is not enough. This is because Bluetooth consists of a number of subprotocols and not all devices support all subprotocols. Furthermore, there is no standardized BT "GPS" protocol. I suspect the "default" BT/GPS protocol would be something like NMEA on top of RFCOMM on top of Bluetooth. And I presume Apple has implemented something proprietary on top of BT for GPS data, which is only supported in the Garmin Glo, Bad Elf and that other one.
Bluetooth - Wikipedia, the free encyclopedia
To make matters worse, the iPad is a fairly closed device. The complete BT stack and the complete Location Services stack is part of the iOS suite, and I doubt SD would be able to access the core, low-level BT functions to implement their own NMEA/RFCOMM stack (or something else) on top of raw BT to support other GPS/BT devices.
All this technical mumbo-jumbo means it's not SDs fault. Air Nav Pro, PocketFMS and similar products would be equally affected. (And would equally benefit from getting an iPad compatible GPS such as the Garmin Glo, Bad Elf and that other one, without having to do a software update or anything.)