diff --git a/README.md b/README.md
index 29fafc4a..8e478f08 100644
--- a/README.md
+++ b/README.md
@@ -24,12 +24,12 @@ Build status: [![Build Status](https://travis-ci.org/PHPMailer/PHPMailer.svg)](h
 
 ## Why you might need it
 
-Many PHP developers utilize email in their code. The only PHP function that supports this is the mail() function. However, it does not provide any assistance for making use of popular features such as HTML-based emails and attachments.
+Many PHP developers utilize email in their code. The only PHP function that supports this is the `mail()` function. However, it does not provide any assistance for making use of popular features such as HTML-based emails and attachments.
 
-Formatting email correctly is surprisingly difficult. There are myriad overlapping RFCs, requiring tight adherence to horribly complicated formatting and encoding rules - the vast majority of code that you'll find online that uses the mail() function directly is just plain wrong!
+Formatting email correctly is surprisingly difficult. There are myriad overlapping RFCs, requiring tight adherence to horribly complicated formatting and encoding rules - the vast majority of code that you'll find online that uses the `mail()` function directly is just plain wrong!
 *Please* don't be tempted to do it yourself - if you don't use PHPMailer, there are many other excellent libraries that you should look at before rolling your own - try SwiftMailer, Zend_Mail, eZcomponents etc.
 
-The PHP mail() function usually sends via a local mail server, typically fronted by a `sendmail` binary on Linux, BSD and OS X platforms, however, Windows usually doesn't include a local mail server; PHPMailer's integrated SMTP implementation allows email sending on Windows platforms without a local mail server.
+The PHP `mail()` function usually sends via a local mail server, typically fronted by a `sendmail` binary on Linux, BSD and OS X platforms, however, Windows usually doesn't include a local mail server; PHPMailer's integrated SMTP implementation allows email sending on Windows platforms without a local mail server.
 
 ## License
 
@@ -105,34 +105,35 @@ if(!$mail->send()) {
 ```
 
 You'll find plenty of examples to play with in the [examples](examples/) folder. They are saved with a `.phps` extension which will make them display as highlighted source in a browser, avoiding the possibility of them running in default installations. You can run them directly from a command line client, or rename them with a `.php` extension and run them via your web server.
+You'll find plenty more to play with in the [examples](https://github.com/PHPMailer/PHPMailer/tree/master/examples) folder.
 
 That's it. You should now be ready to use PHPMailer!
 
 ## Localization
-PHPMailer defaults to English, but in the [language](language/) folder you'll find numerous (46 at the time of writing!) translations for PHPMailer error messages that you may encounter. Their filenames contain [ISO 639-1](http://en.wikipedia.org/wiki/ISO_639-1) language code for the translations, for example `fr` for French. To specify a language, you need to tell PHPMailer which one to use, like this:
+PHPMailer defaults to English, but in the [language](https://github.com/PHPMailer/PHPMailer/language/) folder you'll find numerous (46 at the time of writing!) translations for PHPMailer error messages that you may encounter. Their filenames contain [ISO 639-1](http://en.wikipedia.org/wiki/ISO_639-1) language code for the translations, for example `fr` for French. To specify a language, you need to tell PHPMailer which one to use, like this:
 
 ```php
 // To load the French version
 $mail->setLanguage('fr', '/optional/path/to/language/directory/');
 ```
 
-We welcome corrections and new languages - if you're looking for corrections to do, run the [phpmailerLangTest.php](test/phpmailerLangTest.php) script in the tests folder and it will show any missing translations.
+We welcome corrections and new languages - if you're looking for corrections to do, run the [phpmailerLangTest.php](https://github.com/PHPMailer/PHPMailer/test/phpmailerLangTest.php) script in the tests folder and it will show any missing translations.
 
 ## Documentation
 
 Start reading at the [GitHub wiki](https://github.com/PHPMailer/PHPMailer/wiki). If you're having trouble, this should be the first place you look as it's the most frequently updated.
 
-Examples of how to use PHPMailer for common scenarios can be found in the [examples](examples/) folder. If you're looking for a good starting point, we recommend you start with [the gmail example](examples/gmail.phps).
+Examples of how to use PHPMailer for common scenarios can be found in the [examples](https://github.com/PHPMailer/PHPMailer/tree/master/examples) folder. If you're looking for a good starting point, we recommend you start with [the Gmail example](https://github.com/PHPMailer/PHPMailer/examples/gmail.phps).
 
 Complete generated API documentation is [available online](http://phpmailer.github.io/PHPMailer/).
 
-You'll find some basic user-level docs in the [docs](docs/) folder, and you can generate complete API-level documentation using the [generatedocs.sh](docs/generatedocs.sh) shell script in the docs folder, though you'll need to install [PHPDocumentor](http://www.phpdoc.org) first. You may find [the unit tests](test/phpmailerTest.php) a good source of how to do various operations such as encryption.
+You'll find some basic user-level docs in the [docs](https://github.com/PHPMailer/PHPMailer/tree/master/docs/) folder, and you can generate complete API-level documentation using the [generatedocs.sh](https://github.com/PHPMailer/PHPMailer/docs/generatedocs.sh) shell script in the docs folder, though you'll need to install [PHPDocumentor](http://www.phpdoc.org) first. You may find [the unit tests](https://github.com/PHPMailer/PHPMailer/test/phpmailerTest.php) a good source of how to do various operations such as encryption.
 
-If the documentation doesn't cover what you need, search the [many questions on StackOverflow](http://stackoverflow.com/questions/tagged/phpmailer), and before you ask a question about "SMTP Error: Could not connect to SMTP host.", [read the troubleshooting guide](https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting).
+If the documentation doesn't cover what you need, search the [many questions on Stack Overflow](http://stackoverflow.com/questions/tagged/phpmailer), and before you ask a question about "SMTP Error: Could not connect to SMTP host.", [read the troubleshooting guide](https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting).
 
 ## Tests
 
-There is a PHPUnit test script in the [test](test/) folder. PHPMailer uses PHPUnit 4.8 - we would use 5.0 but we need to run on PHP 5.4.
+There is a PHPUnit test script in the [test](https://github.com/PHPMailer/PHPMailer/tree/master/test/) folder.
 
 Build status: [![Build Status](https://travis-ci.org/PHPMailer/PHPMailer.svg)](https://travis-ci.org/PHPMailer/PHPMailer)
 
diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 94997a41..e243adc3 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -3589,11 +3589,13 @@ class PHPMailer
         if ($this->DKIM_passphrase != '') {
             $privKey = openssl_pkey_get_private($privKeyStr, $this->DKIM_passphrase);
         } else {
-            $privKey = $privKeyStr;
+            $privKey = openssl_pkey_get_private($privKeyStr);
         }
-        if (openssl_sign($signHeader, $signature, $privKey)) {
+        if (openssl_sign($signHeader, $signature, $privKey, 'sha256WithRSAEncryption')) { //sha1WithRSAEncryption
+            openssl_pkey_free($privKey);
             return base64_encode($signature);
         }
+        openssl_pkey_free($privKey);
         return '';
     }
 
@@ -3648,7 +3650,7 @@ class PHPMailer
      */
     public function DKIM_Add($headers_line, $subject, $body)
     {
-        $DKIMsignatureType = 'rsa-sha1'; // Signature & hash algorithms
+        $DKIMsignatureType = 'rsa-sha256'; // Signature & hash algorithms
         $DKIMcanonicalization = 'relaxed/simple'; // Canonicalization of header/body
         $DKIMquery = 'dns/txt'; // Query method
         $DKIMtime = time(); // Signature Timestamp = seconds since 00:00:00 - Jan 1, 1970 (UTC time zone)
@@ -3656,6 +3658,7 @@ class PHPMailer
         $headers = explode($this->LE, $headers_line);
         $from_header = '';
         $to_header = '';
+        $date_header = '';
         $current = '';
         foreach ($headers as $header) {
             if (strpos($header, 'From:') === 0) {
@@ -3664,6 +3667,9 @@ class PHPMailer
             } elseif (strpos($header, 'To:') === 0) {
                 $to_header = $header;
                 $current = 'to_header';
+            } elseif (strpos($header, 'Date:') === 0) {
+                $date_header = $header;
+                $current = 'date_header';
             } else {
                 if (!empty($$current) && strpos($header, ' =?') === 0) {
                     $$current .= $header;
@@ -3674,6 +3680,7 @@ class PHPMailer
         }
         $from = str_replace('|', '=7C', $this->DKIM_QP($from_header));
         $to = str_replace('|', '=7C', $this->DKIM_QP($to_header));
+        $date = str_replace('|', '=7C', $this->DKIM_QP($date_header));
         $subject = str_replace(
             '|',
             '=7C',
@@ -3681,7 +3688,7 @@ class PHPMailer
         ); // Copied header fields (dkim-quoted-printable)
         $body = $this->DKIM_BodyC($body);
         $DKIMlen = strlen($body); // Length of body
-        $DKIMb64 = base64_encode(pack('H*', sha1($body))); // Base64 of packed binary SHA-1 hash of body
+        $DKIMb64 = base64_encode(pack('H*', hash('sha256', $body))); // Base64 of packed binary SHA-256 hash of body
         if ('' == $this->DKIM_identity) {
             $ident = '';
         } else {
@@ -3694,16 +3701,18 @@ class PHPMailer
             $this->DKIM_selector .
             ";\r\n" .
             "\tt=" . $DKIMtime . '; c=' . $DKIMcanonicalization . ";\r\n" .
-            "\th=From:To:Subject;\r\n" .
+            "\th=From:To:Date:Subject;\r\n" .
             "\td=" . $this->DKIM_domain . ';' . $ident . "\r\n" .
             "\tz=$from\r\n" .
             "\t|$to\r\n" .
+            "\t|$date\r\n" .
             "\t|$subject;\r\n" .
             "\tbh=" . $DKIMb64 . ";\r\n" .
             "\tb=";
         $toSign = $this->DKIM_HeaderC(
             $from_header . "\r\n" .
             $to_header . "\r\n" .
+            $date_header . "\r\n" .
             $subject_header . "\r\n" .
             $dkimhdrs
         );