What message are you seeing? Are you having issues connecting your Go 16 to other files on your 15 server or just this file?
If you cannot connect to other files it may be you need to update your server to the latest version v15.0.3
DevCon2Go17 does require FileMaker GO 16 or FileMaker Pro/Advanced 16.
The reason is that it uses several FileMaker 16 specific features.
The app is designed to run directly and local on your device, so please install FileMaker Go 16 on your device (free download from the AppStore) and then download the file from the link below, and open/copy it into FileMaker Go 16.
DevCon2Go17 is NOT designed to run on your server as some features are only working locally.
DevCon2Go17 is btw. Open Source, which means that you can use the feature More... -> Developer Tools -> Unlock when you open the file on your Desktop.