I have customized a version of Survey123 in Appstudio and configured the URL Scheme with "suu".
I have then side loaded my app on my iphone and it works perfectly, well almost.
To my understanding I just need to replace 'arcgis-survey123' with 'suu'. However, when I click the link it gets stuck in the image >> What am I missing?
Note: when I save the link does break and gets replaced with #?itemid=...... However, I am able to crack open the json and change it back to the suu://?itemID= as shown above.
Also, when I copy and paste the link into safari manually it does redirect to my custom Survey123 app and open it. It just doesn't work from Collector 10.4.2 on iOS 10.2.