RE: Workflow approvals using an iPhone or Android
Richard, you can definitely do it, as long as everything is set up correctly.
1. Split brain DNS between the internal and external networks.
2. Changing the default domain of all the users to be whateveryourdomainis.com instead of whateveryourdomainis.local in AD.
(If the users are syncing to MS365 and Azure AD, then these would already be done)
3. Web services set up with a third-party SSL certificate and HTTPS.
4. Setting up external DNS to let web services resolve from the internet.
5. Opening up the appropriate ports on the firewall.
What Derek posted about the links being removed in the native mail apps on iPhone and Android, I have always trained the users to use the Outlook app. More features anyway and just a better experience.
Tapping the approve or deny link on the phone just asks the user to sign in. If DNS and AD is set up correctly, they can just sign in with their email and password and then save it.
Have had this set up since GP 2015 R2. No issues whatsoever.
I hope this helps a bit.
Thanks.
Joe