A remote code execution vulnerability has been found in the Swift Mailer library (swiftmailer/swiftmailer) recently. [See this advisory for details](http://legalhackers.com/advisories/SwiftMailer-Exploit-Remote-Code-Exec-CVE-2016-10074-Vuln.html). If you are not using the default mail() transport, this particular problem does not affect you. Upgrading is of course still recommended!