Earlier we had a bug which crashed iPhone if the date was set to1 January, 1970.
The bug was reported by Reddit userson this thread.
The date of January 1st, 1970 simply means theres no data for the date, reads the post.
No one crafted the email maliciously, it just has no data.
The Jan 1, 1970 has been fixed by Apple in the forthcoming iOS 9.3 software update.
Mail, Contacts, Calendars.
Now exit tweaks and go to Mail and the null messages should be gone.
Go back to configs and re-enable your email account.
This issue only seems to affect Apples stock Mail app and when changing time zones.
Apple has so far not commented on the bug.
source: www.techworm.net