Not compatible with X-Plane 10
As an aside, it would be nice if it worked with the transponder, too. Currently, it only controls com, nav, and ADF.

Archived App
This is an archived listing of the app previously available on the App Store.Enhance your flight simulator experience with this aviation radio addon. Control COM, NAV, and ADF frequencies, and utilize DME for IFR navigation. Supports multiple devices for a comprehensive setup.
1.11
July 10, 2017
This app has been updated by Apple to display the Apple Watch app icon. Improvements for iPhone 6 and 7
MoreFSi Radio is intended for Microsoft Flight Simulator X and X-Plane. It requires a separate server application to be downloaded and run on your computer.
You need to download the free FSi Server application from avioware.com and ensure your iPad and computer running the simulator are on the same network for the connection to be established.
Yes, FSi Radio allows you to use up to 8 iOS devices in your setup. Each device can control a separate instrument or serve as a backup for the primary one.
No, FSi Radio requires an active connection to a flight simulator running on a computer, so it is not usable offline.
FSi Radio is a paid application priced at $4.99. There are no in-app purchases or subscription fees mentioned.
The latest version of FSi Radio is 1.11, which was last updated on July 10, 2017. This indicates a less frequent update schedule.
FSi Radio has an age rating of 4+, making it suitable for a wide range of users.
The provided data does not indicate the presence of advertisements in FSi Radio. It is a paid application.