diff --git a/examples/contentsutf8.html b/examples/contentsutf8.html
index d9fa1d21..bc3ecafa 100644
--- a/examples/contentsutf8.html
+++ b/examples/contentsutf8.html
@@ -16,6 +16,8 @@
   <p>Armenian text: Հաղորդագրությունը դատարկ է</p>
   <p>Czech text: Prázdné tělo zprávy</p>
   <p>Emoji: 🐿💥⛷🚀📱❤️</p>
+  <p>Image data URL (base64)<img src="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==" alt="#"></p>
+  <p>Image data URL (URL-encoded)<img src="data:image/gif,GIF89a%01%00%01%00%00%00%00%21%F9%04%01%0A%00%01%00%2C%00%00%00%00%01%00%01%00%00%02%02L%01%00%3B" alt="#"></p>
 </div>
 </body>
 </html>
diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index b8e9454b..e6591883 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -2513,13 +2513,13 @@ class PHPMailer
                     if ($this->isError()) {
                         return '';
                     }
-                    $mime[] = $this->LE . $this->LE;
+                    $mime[] = $this->LE;
                 } else {
                     $mime[] = $this->encodeFile($path, $encoding);
                     if ($this->isError()) {
                         return '';
                     }
-                    $mime[] = $this->LE . $this->LE;
+                    $mime[] = $this->LE;
                 }
             }
         }
@@ -2728,23 +2728,12 @@ class PHPMailer
      * According to RFC2045 section 6.7.
      * @access public
      * @param string $string The text to encode
-     * @param integer $line_max Number of chars allowed on a line before wrapping
+     * @param integer $line_max Number of chars allowed on a line before wrapping, for compatibility with old versions
      * @return string
-     * @link http://www.php.net/manual/en/function.quoted-printable-decode.php#89417 Adapted from this comment
      */
     public function encodeQP($string, $line_max = 76)
     {
-        // Use native function if it's available (>= PHP5.3)
-        if (function_exists('quoted_printable_encode')) {
-            return quoted_printable_encode($string);
-        }
-        // Fall back to a pure PHP implementation
-        $string = str_replace(
-            ['%20', '%0D%0A.', '%0D%0A', '%'],
-            [' ', "\r\n=2E", "\r\n", '='],
-            rawurlencode($string)
-        );
-        return preg_replace('/[^\r\n]{' . ($line_max - 3) . '}[^=\r\n]{2}/', "$0=\r\n", $string);
+        return quoted_printable_encode($string);
     }
 
     /**
@@ -2918,6 +2907,22 @@ class PHPMailer
         return true;
     }
 
+    /**
+     * Check if an embedded attachment is present with this cid.
+     * @access protected
+     * @param $cid
+     * @return bool
+     */
+    protected function cidExists($cid)
+    {
+        foreach ($this->attachment as $attachment) {
+            if ('inline' == $attachment[6] and $cid == $attachment[7]) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * Check if an inline attachment is present.
      * @access public
@@ -3214,21 +3219,28 @@ class PHPMailer
         if (array_key_exists(2, $images)) {
             foreach ($images[2] as $imgindex => $url) {
                 // Convert data URIs into embedded images
-                if (preg_match('#^data:(image[^;,]*)(;base64)?,#', $url, $match)) {
-                    $data = substr($url, strpos($url, ','));
-                    if ($match[2]) {
-                        $data = base64_decode($data);
+                //e.g. "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw=="
+                if (preg_match('#^data:(image/(?:jpe?g|gif|png));?(base64)?,(.+)#', $url, $match)) {
+                    if (count($match) == 4 and 'base64' == $match[2]) {
+                        $data = base64_decode($match[3]);
+                    } elseif ('' == $match[2]) {
+                        $data = rawurldecode($match[3]);
                     } else {
-                        $data = rawurldecode($data);
+                        //Not recognised so leave it alone
+                        continue;
                     }
-                    $cid = md5($url) . '@phpmailer.0'; // RFC2392 S 2
-                    if ($this->addStringEmbeddedImage($data, $cid, 'embed' . $imgindex, 'base64', $match[1])) {
-                        $message = str_replace(
-                            $images[0][$imgindex],
-                            $images[1][$imgindex] . '="cid:' . $cid . '"',
-                            $message
-                        );
+                    //Hash the decoded data, not the URL so that the same data-URI image used in multiple places
+                    //will only be embedded once, even if it used a different encoding
+                    $cid = md5($data) . '@phpmailer.0'; // RFC2392 S 2
+
+                    if (!$this->cidExists($cid)) {
+                        $this->addStringEmbeddedImage($data, $cid, 'embed' . $imgindex, 'base64', $match[1]);
                     }
+                    $message = str_replace(
+                        $images[0][$imgindex],
+                        $images[1][$imgindex] . '="cid:' . $cid . '"',
+                        $message
+                    );
                 } elseif (substr($url, 0, 4) !== 'cid:' and !preg_match('#^[a-z][a-z0-9+.-]*://#i', $url)) {
                     // Do not change urls for absolute images (thanks to corvuscorax)
                     // Do not change urls that are already inline images
@@ -3433,14 +3445,13 @@ class PHPMailer
         if (false !== $qpos) {
             $filename = substr($filename, 0, $qpos);
         }
-        $pathinfo = self::mb_pathinfo($filename);
-        return self::_mime_types($pathinfo['extension']);
+        $ext = self::mb_pathinfo($filename, PATHINFO_EXTENSION);
+        return self::_mime_types($ext);
     }
 
     /**
      * Multi-byte-safe pathinfo replacement.
-     * Drop-in replacement for pathinfo(), but multibyte-safe, cross-platform-safe, old-version-safe.
-     * Works similarly to the one in PHP >= 5.2.0
+     * Drop-in replacement for pathinfo(), but multibyte- and cross-platform-safe
      * @link http://www.php.net/manual/en/function.pathinfo.php#107461
      * @param string $path A filename or path, does not need to exist as a file
      * @param integer|string $options Either a PATHINFO_* constant,
diff --git a/test/bootstrap.php b/test/bootstrap.php
index 1b9cdec2..e2141250 100644
--- a/test/bootstrap.php
+++ b/test/bootstrap.php
@@ -5,8 +5,3 @@
 
 ini_set('sendmail_path', '/usr/sbin/sendmail -t -i ');
 require_once '../vendor/autoload.php';
-spl_autoload_register(
-    function ($class) {
-        require_once strtr($class, '\\_', '//') . '.php';
-    }
-);
diff --git a/test/phpmailerTest.php b/test/phpmailerTest.php
index cf7e7bda..eb678019 100644
--- a/test/phpmailerTest.php
+++ b/test/phpmailerTest.php
@@ -851,7 +851,7 @@ EOT;
     public function testHtmlUtf8()
     {
         $this->Mail->isHTML(true);
-        $this->Mail->Subject .= ": UTF-8 HTML";
+        $this->Mail->Subject .= ": UTF-8 HTML Пустое тело сообщения";
         $this->Mail->CharSet = 'UTF-8';
 
         $this->Mail->Body = <<<EOT
@@ -941,8 +941,8 @@ EOT;
         $this->Mail->AltBody = '';
         //Uses internal HTML to text conversion
         $this->Mail->msgHTML($message, realpath($this->INCLUDE_DIR . '/examples'));
-        $this->Mail->Subject .= ': msgHTML';
-        $this->Mail->addAddress('user@example.com');
+        $sub = $this->Mail->Subject . ': msgHTML';
+        $this->Mail->Subject .= $sub;
 
         $this->assertNotEmpty($this->Mail->Body, 'Body not set by msgHTML');
         $this->assertNotEmpty($this->Mail->AltBody, 'AltBody not set by msgHTML');
@@ -957,9 +957,7 @@ EOT;
                 return strtoupper(strip_tags($html));
             }
         );
-        $this->Mail->Subject .= ' + custom html2text';
-        $this->assertNotEmpty($this->Mail->AltBody, 'Custom AltBody not set by msgHTML');
-
+        $this->Mail->Subject = $sub . ' + custom html2text';
         $this->assertTrue($this->Mail->send(), $this->Mail->ErrorInfo);
     }
 
@@ -1000,9 +998,9 @@ EOT;
         if (!$this->Mail->addStringEmbeddedImage(
             file_get_contents(realpath($this->INCLUDE_DIR . '/examples/images/phpmailer_mini.png')),
             md5('phpmailer_mini.png').'@phpmailer.0',
-            '', //intentionally empty name
+            '', //Intentionally empty name
             'base64',
-            'image/png',
+            '', //Intentionally empty MIME type
             'inline'
         )) {
             $this->assertTrue(false, $this->Mail->ErrorInfo);
@@ -1544,6 +1542,11 @@ EOT;
             $this->Mail->encodeQ("Nov\xc3\xa1=", 'text'),
             'Q Encoding (text) failed 2'
         );
+
+        $this->assertEquals($this->Mail->encodeString('hello', 'binary'), 'hello', 'Binary encoding changed input');
+        $this->Mail->ErrorInfo = '';
+        $this->Mail->encodeString('hello', 'asdfghjkl');
+        $this->assertNotEmpty($this->Mail->ErrorInfo, 'Invalid encoding not detected');
     }
 
     /**
@@ -1854,6 +1857,11 @@ EOT;
             '/mnt/files',
             'Dirname path element not matched'
         );
+        $this->assertEquals(
+            PHPMailer::mb_pathinfo($a, PATHINFO_BASENAME),
+            '飛兒樂 團光茫.mp3',
+            'Basename path element not matched'
+        );
         $this->assertEquals(PHPMailer::mb_pathinfo($a, 'filename'), '飛兒樂 團光茫', 'Filename path element not matched');
         $a = 'c:\mnt\files\飛兒樂 團光茫.mp3';
         $q = PHPMailer::mb_pathinfo($a);
@@ -1861,7 +1869,37 @@ EOT;
         $this->assertEquals($q['basename'], '飛兒樂 團光茫.mp3', 'Windows basename not matched');
         $this->assertEquals($q['extension'], 'mp3', 'Windows extension not matched');
         $this->assertEquals($q['filename'], '飛兒樂 團光茫', 'Windows filename not matched');
+
+        $this->assertEquals(
+            PHPMailer::filenameToType('abc.jpg?xyz=1'),
+            'image/jpeg',
+            'Query string not ignored in filename'
+        );
+        $this->assertEquals(
+            PHPMailer::filenameToType('abc.xyzpdq'),
+            'application/octet-stream',
+            'Default MIME type not applied to unknown extension'
+        );
+        
+        //Line break normalization
+        $eol = $this->Mail->LE;
+        $b1 = "1\r2\r3\r";
+        $b2 = "1\n2\n3\n";
+        $b3 = "1\r\n2\r3\n";
+        $this->Mail->LE = "\n";
+        $t1 = "1{$this->Mail->LE}2{$this->Mail->LE}3{$this->Mail->LE}";
+        $this->assertEquals($this->Mail->fixEOL($b1), $t1, 'Failed to normalize line breaks (1)');
+        $this->assertEquals($this->Mail->fixEOL($b2), $t1, 'Failed to normalize line breaks (2)');
+        $this->assertEquals($this->Mail->fixEOL($b3), $t1, 'Failed to normalize line breaks (3)');
+        $this->Mail->LE = "\r\n";
+        $t1 = "1{$this->Mail->LE}2{$this->Mail->LE}3{$this->Mail->LE}";
+        $this->assertEquals($this->Mail->fixEOL($b1), $t1, 'Failed to normalize line breaks (4)');
+        $this->assertEquals($this->Mail->fixEOL($b2), $t1, 'Failed to normalize line breaks (5)');
+        $this->assertEquals($this->Mail->fixEOL($b3), $t1, 'Failed to normalize line breaks (6)');
+        $this->Mail->LE = $eol;
+
     }
+
     public function testBadSMTP()
     {
         $this->Mail->smtpConnect();
@@ -2087,6 +2125,7 @@ EOT;
     /**
      * Test SMTP host connections.
      * This test can take a long time, so run it last
+     * @group slow
      */
     public function testSmtpConnect()
     {