Re:Apple’s announcement on artificial intelligence is a big ...
by e28eta on Tuesday June 14, 2016 @10:30AM
(#11902212)
Making 'mailto' a bad choice, but iOS does allow you to register URL protocol handlers (better choice: 'x-fooapp:'). I believe it's undefined which app is chosen in the case of conflicts.
ios hasnt previously let you set a default app for protocols or filetypes.