Good to see this added in the latest release, which shows up as an alternative choice to FLARM, XPlane and SkyView.

Couple of questions:
‌‌
1) W‌hich features of the protocol are supported?
I‌'m assuming it would mainly be traffic reports so could display any nearby aircraft that it knows about, which could include those reported from ADS-B groundstations in the US using TIS-B. But would it support METAR, TAF or NEXRAD weather information (if flying in the US, and can receive it through FIS-B via the UAT frequency)? Not relevant elsewhere, so I could understand if you didn't.

2) D‌oes this require the GDL90 compatible device to become the GPS position source, instead of the tablet's built-in GPS? If that is the case, it could act as GPS source without ever reporting any other traffic.

I found an old (2007) copy of the GDL90 protocol specification here
https://www.faa.gov/nextgen/programs/adsb/Archival/media/GDL90_Public_ICD_RevA.PDF

T‌hanks‌

‌‌‌EDIT: I'm using version 3.7.0.58 on an Apple iPad 4

--- CPL/IR/FI based in South of England

That device cannot currently be used. We will evaluate this going forward if there is significant demand for it. Bear in mind that it has no barometer, so (I believe) it is not possible to tell accurately the height difference between ownship and other traffic.