Turn off mail threads on your iPhone in iOS 10
With the introduction of iOS 10, Apple introduced message threads to it's Mail App. The only problem is that it switched it on by default and many of you hate it - Don't worry though there is an easy way to turn it off.
To turn off mail threads, open Settings, scroll down and select Mail, then turn off all the buttons under "Threading".
Done! Now you'll only see the most recent messages as they arrive and not grouped together by subject.