If the pre-release/rumor article I posted early is the real dongle, this is how they say it worked:
"When the Lightning to 3.5 mm adapter is plugged into a device running iOS 9 or lower, the software displays an incompatibility message to the user, but when used on devices with a beta of iOS 10 installed, the dongle appears to work "immediately" without any issues. The author also notes that if headphones are plugged into both the standard headphone jack on a current iPhone and the adapter connected to Lightning, the device gives priority to the Lightning port for audio output. "
That requirement for iOS 10 for this adapter -- which is stated already on the product information page for the replacement adapter at Apple's web site -- is definitely curious, perhaps suggesting that this dongle isn't using the same standard USB Audio interface, given that other DACs work with iOS 9 (and earlier versions, maybe iOS 8?) already through the CCK adapter (I have a couple, the older without Lightning pass-through charging, and the new one with it), or directly with a regular Lightning cable to MFi certified devices like my SoundBlaster E5 DAC/amp.