MyBB Community Forums

Detailed description of your problem, including steps to reproduce if necessary
Just change your email address and check email subject (Change of Email at {1})

URL to your forum/URL to specific problematic page
Any with MyBB 1.8

New installation or upgrade (from which version of MyBB)
Mine was new, MyBB.com have updated.

Test user account (if it requires additional permissions)
Not needed. Use your account on community.mybb.com

Screenshot or error text, verbatim
Sure: http://i.imgur.com/vrcY2g6.png

EDIT:
Found a solution. There's missing $lang->emailsubject_changeemail
https://github.com/mybb/mybb/blob/featur....php#L1261

Just insert between my_mail and $mail_message this string:
$lang->emailsubject_changeemail = $lang->sprintf($lang->emailsubject_changeemail, $mybb->settings['bbname']);

It'll be fixed in 1.8.1: https://github.com/mybb/mybb/issues/1377