diff --git a/.gitignore b/.gitignore
index e1294abd..1006c116 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,6 +2,5 @@ docs/phpdoc/
 test/message.txt
 test/testbootstrap.php
 test/*.pem
-.idea
 build/
 vendor/
diff --git a/VERSION b/VERSION
index c95ed737..56f1219b 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.2.15
\ No newline at end of file
+5.2.16
\ No newline at end of file
diff --git a/changelog.md b/changelog.md
index e871ab2d..39b7c5a8 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,13 @@
 # ChangeLog
 
+## Version 5.2.16 (June 6th 2016)
+* Added DKIM example
+* Fixed empty additional_parameters problem
+* Fixed wrong version number in VERSION file!
+* Improve line-length tests
+* Use instance settings for SMTP::connect by default
+* Use more secure auth mechanisms first
+
 ## Version 5.2.15 (May 10th 2016)
 * Added ability to inject custom address validators, and set the default validator
 * Fix TLS 1.2 compatibility
diff --git a/class.phpmailer.php b/class.phpmailer.php
index 14842160..f9013ebb 100644
--- a/class.phpmailer.php
+++ b/class.phpmailer.php
@@ -31,7 +31,7 @@ class PHPMailer
      * The PHPMailer Version number.
      * @var string
      */
-    public $Version = '5.2.15';
+    public $Version = '5.2.16';
 
     /**
      * Email priority.
@@ -395,7 +395,7 @@ class PHPMailer
 
     /**
      * DKIM Identity.
-     * Usually the email address used as the source of the email
+     * Usually the email address used as the source of the email.
      * @var string
      */
     public $DKIM_identity = '';
@@ -681,7 +681,9 @@ class PHPMailer
         } else {
             $subject = $this->encodeHeader($this->secureHeader($subject));
         }
-        if (ini_get('safe_mode') || !($this->UseSendmailOptions)) {
+        //Can't use additional_parameters in safe_mode
+        //@link http://php.net/manual/en/function.mail.php
+        if (ini_get('safe_mode') or !$this->UseSendmailOptions) {
             $result = @mail($to, $subject, $body, $header);
         } else {
             $result = @mail($to, $subject, $body, $header, $params);
@@ -1425,9 +1427,9 @@ class PHPMailer
         }
         $to = implode(', ', $toArr);
 
-        if (empty($this->Sender)) {
-            $params = ' ';
-        } else {
+        $params = null;
+        //This sets the SMTP envelope sender which gets turned into a return-path header by the receiver
+        if (!empty($this->Sender)) {
             $params = sprintf('-f%s', $this->Sender);
         }
         if ($this->Sender != '' and !ini_get('safe_mode')) {
@@ -1435,7 +1437,7 @@ class PHPMailer
             ini_set('sendmail_from', $this->Sender);
         }
         $result = false;
-        if ($this->SingleTo && count($toArr) > 1) {
+        if ($this->SingleTo and count($toArr) > 1) {
             foreach ($toArr as $toAddr) {
                 $result = $this->mailPassthru($toAddr, $this->Subject, $body, $header, $params);
                 $this->doCallback($result, array($toAddr), $this->cc, $this->bcc, $this->Subject, $body, $this->From);
diff --git a/class.pop3.php b/class.pop3.php
index 9b68bfa6..56ad1bfc 100644
--- a/class.pop3.php
+++ b/class.pop3.php
@@ -34,7 +34,7 @@ class POP3
      * @var string
      * @access public
      */
-    public $Version = '5.2.15';
+    public $Version = '5.2.16';
 
     /**
      * Default POP3 port number.
diff --git a/class.smtp.php b/class.smtp.php
index d5e9e0fa..0c016f12 100644
--- a/class.smtp.php
+++ b/class.smtp.php
@@ -30,7 +30,7 @@ class SMTP
      * The PHPMailer SMTP version number.
      * @var string
      */
-    const VERSION = '5.2.15';
+    const VERSION = '5.2.16';
 
     /**
      * SMTP line break constant.
@@ -81,7 +81,7 @@ class SMTP
      * @deprecated Use the `VERSION` constant instead
      * @see SMTP::VERSION
      */
-    public $Version = '5.2.15';
+    public $Version = '5.2.16';
 
     /**
      * SMTP server port number.
diff --git a/examples/DKIM.phps b/examples/DKIM.phps
new file mode 100644
index 00000000..e3d2bae0
--- /dev/null
+++ b/examples/DKIM.phps
@@ -0,0 +1,38 @@
+<?php
+/**
+ * This example shows how to use DKIM message authentication with PHPMailer.
+ * There's more to using DKIM than just this code - check out this article:
+ * @link https://yomotherboard.com/how-to-setup-email-server-dkim-keys/
+ * See also the DKIM code in the PHPMailer unit tests,
+ * which shows how to make a key pair from PHP.
+ */
+
+require '../PHPMailerAutoload.php';
+
+//Create a new PHPMailer instance
+$mail = new PHPMailer;
+//Set who the message is to be sent from
+$mail->setFrom('from@example.com', 'First Last');
+//Set an alternative reply-to address
+$mail->addReplyTo('replyto@example.com', 'First Last');
+//Set who the message is to be sent to
+$mail->addAddress('whoto@example.com', 'John Doe');
+//Set the subject line
+$mail->Subject = 'PHPMailer DKIM test';
+//This should be the same as the domain of your From address
+$mail->DKIM_domain = 'example.com';
+//Path to your private key file
+$mail->DKIM_private = 'dkim_private.pem';
+//Set this to your own selector
+$mail->DKIM_selector = 'phpmailer';
+//If your private key has a passphrase, set it here
+$mail->DKIM_passphrase = '';
+//The identity you're signing as - usually your From address
+$mail->DKIM_identity = $mail->From;
+
+//send the message, check for errors
+if (!$mail->send()) {
+    echo "Mailer Error: " . $mail->ErrorInfo;
+} else {
+    echo "Message sent!";
+}