With the release of iOS 4.0, the Mail app started grouping e-mail messages by threads. The original e-mail plus all the replies show up neatly as one entry, with a small, boxed number on the right-hand side showing how many messages are grouped. While this feature can save you time and energy, it can also get cumbersome if you're looking for a specific message on a thread and don't know which one it is. Here's how you can disable the threaded message feature:
- Open Settings> Mail, Contacts, Calendars.
- Swipe the Organize By Thread switch to OFF.