Add support for SMTP servers with StartTLS

utils/config.go

@@ -85,6 +85,7 @@ type EmailSettings struct {
 	SMTPPassword         string
 	SMTPServer           string
 	UseTLS               bool
+	UseStartTLS          bool
 	FeedbackEmail        string
 	FeedbackName         string
 	ApplePushServer      string

utils/mail.go

@@ -73,6 +73,12 @@ func newSMTPClient(conn net.Conn) (*smtp.Client, *model.AppError) {
 		if err = c.Auth(auth); err != nil {
 			return nil, model.NewAppError("SendMail", "Failed to authenticate on SMTP server", err.Error())
 		}
+	} else if Cfg.EmailSettings.UseStartTLS {
+		tlsconfig := &tls.Config{
+			InsecureSkipVerify: true,
+			ServerName:         host,
+		}
+		c.StartTLS(tlsconfig)
 	}
 	return c, nil
 }