I have universal links implemented, working fine. I send an email to a user, then iOS will open the app if it's installed, or it will go to my website if not. At which point, I use apache mod_rewrite to redirect to a page which gives information on installing the app.
However, some users have hotmail accounts with advance threat protection enabled. So the URL they receive in their inbox is wrapped with https://nam10.safelinks.protection.outlook.com/? ... which when you follow it, eventually redirect to the correct url. Which opens the app fine on iOS 14, however on iOS 13 it takes me to the web site, regardless if the app is installed or not.
So on iOS 13 the safe links protection totally breaks the universal link configuration.
I'm trying to find way around this. My current thought is to use mod_rewrite to forward to a custom URL, but struggling with that, as mod_rewrite likes to add http:// in front of my redirects.
Has anyone else experienced this? I've seen one stack overflow post on the subject, but not with a solution that works for me.