Manual:$wgEnableUserEmail

Email settings: $wgEnableUserEmail
Set to true to enable user-to-user email.
Introduced in version:	1.4.0
Removed in version:	Still in use
Allowed values:	(boolean)
Default value:	true (1.5+) false (1.4)
Other settings: Alphabetical | By function

Details

Set to true to enable user-to-user email via Special:Emailuser. This can potentially be abused, as it's hard to track. This setting can be used to check if SMTP is set up correctly on your wiki.

Requires $wgEnableEmail to be true as well.

See also

• $wgEnableEmail
• $wgUserEmailUseReplyTo - useful to fix email submission in older versions of MediaWiki with recent mailservers