SwiftMailer is loaded in the versions special page.
Wiki gives this error: [0ddb29d7] /wiki/index.php/Especial:Alterar_e-mail MWException from line 291 of /var/www/wiki/includes/mail/UserMailer.php: PEAR mail package is not installed
Installed composer.phar and run in the SwiftMailer page, and the output was this:
Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update
Generating autoload files