The URL scheme has been implemented for ESRI mobile apps (https://community.esri.com/groups/survey123/blog/2016/07/30/understanding-survey123s-custom-url-sche...) but leveraging the iOS SDK to launch third party and system apps would extend the functionality of Survey123.
For example, I am designing a Survey123 survey for bird counts that occur within 3 minute observation intervals. Enabling the user to launch a timer at the start of a count and launch a gps logger to record tracks would be hugely useful.
Is this do-able or are there complex back-end modifications that limit such free inter-app communication?