diff --git a/.travis.yml b/.travis.yml
index f16d8264..6eacab3a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -3,7 +3,6 @@ php:
   - 7.0
   - 5.6
   - 5.5
-  - 5.4
   - hhvm
 matrix:
   allow_failures:
diff --git a/README.md b/README.md
index f52de0cb..aeb87a13 100644
--- a/README.md
+++ b/README.md
@@ -41,7 +41,7 @@ software availability and distribution.
 PHPMailer is available on [Packagist](https://packagist.org/packages/phpmailer/phpmailer) (using semantic versioning), and installation via composer is the recommended way to install PHPMailer. Just add this line to your `composer.json` file:
 
 ```json
-"phpmailer/phpmailer": "~5.4"
+"phpmailer/phpmailer": "~5.5"
 ```
 
 or run
@@ -132,7 +132,7 @@ If the documentation doesn't cover what you need, search the [many questions on
 
 ## Tests
 
-There is a PHPUnit test script in the [test](https://github.com/PHPMailer/PHPMailer/tree/master/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. PHPMailer uses PHPUnit 4.8 - we would use 5.x but we need to run on PHP 5.5.
 
 Build status: [![Build Status](https://travis-ci.org/PHPMailer/PHPMailer.svg)](https://travis-ci.org/PHPMailer/PHPMailer)
 
diff --git a/VERSION b/VERSION
index 1e20ec35..c7ba1e87 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-5.4.0
\ No newline at end of file
+5.5.0
\ No newline at end of file
diff --git a/changelog.md b/changelog.md
index eebb66e5..ff40e6ba 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,12 +1,12 @@
 # ChangeLog
 
-## Version 5.4
-This is a major update that breaks backwards compatibility. To emphasise that this release requires PHP 5.4, this release is called **5.4**, **not 5.3**!
+## Version 5.5
+This is a major update that breaks backwards compatibility. To emphasise that this release requires PHP 5.5, this release is called **5.5**, **not 5.3**!
 
-* Requires PHP 5.4 or later
+* Requires PHP 5.5 or later
 * Uses the `PHPMailer\PHPMailer` namespace
 * File structure simplified, classes live in the `src/` folder
-* Custom autoloader has been removed, now PSR-4 compatible
+* Custom autoloader has been removed, now PSR-4 compatible: **use composer**!
 * Classes renamed to make use of the namespace
 * `Extras` classes have been removed - use packages from packagist.org instead
 * All elements previously marked as deprecated have been removed:
diff --git a/examples/code_generator.phps b/examples/code_generator.phps
index 2d998e20..f1ae8b51 100644
--- a/examples/code_generator.phps
+++ b/examples/code_generator.phps
@@ -4,6 +4,9 @@
  * revised, updated and corrected 27/02/2013
  * by matt.sturdy@gmail.com
  */
+
+namespace PHPMailer\PHPMailer;
+
 require '../vendor/autoload.php';
 
 $CFG['smtp_debug'] = 2; //0 == off, 1 for client output, 2 for client and server
@@ -40,7 +43,8 @@ $results_messages = [];
 
 // $example_code represents the "final code" that we're using, and will
 // be shown to the user at the end.
-$example_code = "\nrequire_once '../PHPMailerAutoload.php';";
+$example_code = "<?php\nnamespace PHPMailer\\PHPMailer;";
+$example_code .= "\nrequire_once 'vendor/autoload.php';";
 $example_code .= "\n\n\$results_messages = [];";
 
 $mail = new PHPMailer(true);  //PHPMailer instance with exceptions enabled
@@ -51,23 +55,23 @@ $example_code .= "\n\n\$mail = new PHPMailer(true);";
 $example_code .= "\n\$mail->CharSet = 'utf-8';";
 $example_code .= "\nini_set('default_charset', 'UTF-8');";
 
-class phpmailerAppException extends phpmailerException
+class AppException extends Exception
 {
 }
 
-$example_code .= "\n\nclass phpmailerAppException extends phpmailerException {}";
+$example_code .= "\n\nclass AppException extends Exception {}";
 $example_code .= "\n\ntry {";
 
 try {
     if (isset($_POST["submit"]) && $_POST['submit'] == "Submit") {
         $to = $_POST['To_Email'];
         if (!PHPMailer::validateAddress($to)) {
-            throw new phpmailerAppException("Email address " . $to . " is invalid -- aborting!");
+            throw new AppException("Email address " . $to . " is invalid -- aborting!");
         }
 
         $example_code .= "\n\$to = '{$_POST['To_Email']}';";
         $example_code .= "\nif(!PHPMailer::validateAddress(\$to)) {";
-        $example_code .= "\n  throw new phpmailerAppException(\"Email address \" . " .
+        $example_code .= "\n  throw new AppException(\"Email address \" . " .
             "\$to . \" is invalid -- aborting!\");";
         $example_code .= "\n}";
 
@@ -113,7 +117,7 @@ try {
                 $example_code .= "\n\$mail->isQmail();";
                 break;
             default:
-                throw new phpmailerAppException('Invalid test_type provided');
+                throw new AppException('Invalid test_type provided');
         }
 
         try {
@@ -157,8 +161,8 @@ try {
                     $example_code .= "\n\$mail->addCC(\"$value\");";
                 }
             }
-        } catch (phpmailerException $e) { //Catch all kinds of bad addressing
-            throw new phpmailerAppException($e->getMessage());
+        } catch (Exception $e) { //Catch all kinds of bad addressing
+            throw new AppException($e->getMessage());
         }
         $mail->Subject = $_POST['Subject'] . ' (PHPMailer test using ' . strtoupper($_POST['test_type']) . ')';
         $example_code .= "\n\$mail->Subject  = \"" . $_POST['Subject'] .
@@ -190,21 +194,21 @@ try {
             strtoupper($_POST['test_type']) . "\";";
         $example_code .= "\n}";
         $example_code .= "\ncatch (phpmailerException \$e) {";
-        $example_code .= "\n  throw new phpmailerAppException('Unable to send to: ' . \$to. ': '.\$e->getMessage());";
+        $example_code .= "\n  throw new AppException('Unable to send to: ' . \$to. ': '.\$e->getMessage());";
         $example_code .= "\n}";
 
         try {
             $mail->send();
             $results_messages[] = "Message has been sent using " . strtoupper($_POST["test_type"]);
-        } catch (phpmailerException $e) {
-            throw new phpmailerAppException("Unable to send to: " . $to . ': ' . $e->getMessage());
+        } catch (Exception $e) {
+            throw new AppException("Unable to send to: " . $to . ': ' . $e->getMessage());
         }
     }
-} catch (phpmailerAppException $e) {
+} catch (AppException $e) {
     $results_messages[] = $e->errorMessage();
 }
 $example_code .= "\n}";
-$example_code .= "\ncatch (phpmailerAppException \$e) {";
+$example_code .= "\ncatch (AppException \$e) {";
 $example_code .= "\n  \$results_messages[] = \$e->errorMessage();";
 $example_code .= "\n}";
 $example_code .= "\n\nif (count(\$results_messages) > 0) {";
@@ -356,9 +360,9 @@ $example_code .= "\n}";
 </head>
 <body>
 <?php
-if (version_compare(PHP_VERSION, '5.4.0', '<')) {
+if (version_compare(PHP_VERSION, '5.5.0', '<')) {
     echo 'Current PHP version: ' . phpversion() . "<br>";
-    echo exit("ERROR: Wrong PHP version. Must be PHP 5.4 or later.");
+    echo exit("ERROR: Wrong PHP version. Must be PHP 5.5 or later.");
 }
 
 if (count($results_messages) > 0) {
diff --git a/examples/mailing_list.phps b/examples/mailing_list.phps
index 9e13c15d..c115b2e0 100644
--- a/examples/mailing_list.phps
+++ b/examples/mailing_list.phps
@@ -36,7 +36,7 @@ $mysql = mysqli_connect('localhost', 'username', 'password');
 mysqli_select_db($mysql, 'mydb');
 $result = mysqli_query($mysql, 'SELECT full_name, email, photo FROM mailinglist WHERE sent = false');
 
-foreach ($result as $row) { //This iterator syntax only works in PHP 5.4+
+foreach ($result as $row) {
     $mail->addAddress($row['email'], $row['full_name']);
     if (!empty($row['photo'])) {
         $mail->addStringAttachment($row['photo'], 'YourPhoto.jpg'); //Assumes the image data is stored in the DB
diff --git a/examples/send_file_upload.phps b/examples/send_file_upload.phps
index 42c4509e..bd15e8b3 100644
--- a/examples/send_file_upload.phps
+++ b/examples/send_file_upload.phps
@@ -22,19 +22,19 @@ if (array_key_exists('userfile', $_FILES)) {
         // Attach the uploaded file
         $mail->addAttachment($uploadfile, 'My uploaded file');
         if (!$mail->send()) {
-            $msg = "Mailer Error: " . $mail->ErrorInfo;
+            $msg .= "Mailer Error: " . $mail->ErrorInfo;
         } else {
-            $msg = "Message sent!";
+            $msg .= "Message sent!";
         }
     } else {
-        $msg = 'Failed to move file to ' . $uploadfile;
+        $msg .= 'Failed to move file to ' . $uploadfile;
     }
 }
 ?>
 <!DOCTYPE html>
 <html>
 <head>
-    <meta charset="utf-8"/>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
     <title>PHPMailer Upload</title>
 </head>
 <body>
diff --git a/examples/send_multiple_file_upload.phps b/examples/send_multiple_file_upload.phps
new file mode 100644
index 00000000..ddb76146
--- /dev/null
+++ b/examples/send_multiple_file_upload.phps
@@ -0,0 +1,51 @@
+<?php
+/**
+ * PHPMailer multiple files upload and send example
+ */
+$msg = '';
+if (array_key_exists('userfile', $_FILES)) {
+
+    // Create a message
+    // This should be somewhere in your include_path
+    require '../PHPMailerAutoload.php';
+    $mail = new PHPMailer;
+    $mail->setFrom('from@example.com', 'First Last');
+    $mail->addAddress('whoto@example.com', 'John Doe');
+    $mail->Subject = 'PHPMailer file sender';
+    $mail->msgHTML('My message body');
+    //Attach multiple files one by one
+    for ($ct = 0; $ct < count($_FILES['userfile']['tmp_name']); $ct++) {
+        $uploadfile = tempnam(sys_get_temp_dir(), sha1($_FILES['userfile']['name'][$ct]));
+        $filename = $_FILES['userfile']['name'][$ct];
+        if (move_uploaded_file($_FILES['userfile']['tmp_name'][$ct], $uploadfile)) {
+            $mail->addAttachment($uploadfile, $filename);
+        } else {
+            $msg .= 'Failed to move file to ' . $uploadfile;
+        }
+    }
+    if (!$mail->send()) {
+        $msg .= "Mailer Error: " . $mail->ErrorInfo;
+    } else {
+        $msg .= "Message sent!";
+    }
+}
+?>
+<!DOCTYPE html>
+<html>
+<head>
+    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
+    <title>PHPMailer Upload</title>
+</head>
+<body>
+<?php if (empty($msg)) { ?>
+    <form method="post" enctype="multipart/form-data">
+        <input type="hidden" name="MAX_FILE_SIZE" value="100000">
+        Select one or more files:
+        <input name="userfile[]" type="file" multiple="multiple">
+        <input type="submit" value="Send Files">
+    </form>
+<?php } else {
+    echo $msg;
+} ?>
+</body>
+</html>
diff --git a/examples/smtp_check.phps b/examples/smtp_check.phps
index bc3046ea..b15b3f36 100644
--- a/examples/smtp_check.phps
+++ b/examples/smtp_check.phps
@@ -18,24 +18,39 @@ $smtp = new SMTP;
 $smtp->do_debug = SMTP::DEBUG_CONNECTION;
 
 try {
-//Connect to an SMTP server
-    if ($smtp->connect('mail.example.com', 25)) {
-        //Say hello
-        if ($smtp->hello('localhost')) { //Put your host name in here
-            //Authenticate
-            if ($smtp->authenticate('username', 'password')) {
-                echo "Connected ok!";
-            } else {
-                throw new Exception('Authentication failed: ' . $smtp->getLastReply());
-            }
-        } else {
-            throw new Exception('HELO failed: '. $smtp->getLastReply());
-        }
-    } else {
+    //Connect to an SMTP server
+    if (!$smtp->connect('mail.example.com', 25)) {
         throw new Exception('Connect failed');
     }
+    //Say hello
+    if (!$smtp->hello(gethostname())) {
+        throw new Exception('EHLO failed: ' . $smtp->getError()['error']);
+    }
+    //Get the list of ESMTP services the server offers
+    $e = $smtp->getServerExtList();
+    //If server can do TLS encryption, use it
+    if (array_key_exists('STARTTLS', $e)) {
+        $tlsok = $smtp->startTLS();
+        if (!$tlsok) {
+            throw new Exception('Failed to start encryption: ' . $smtp->getError()['error']);
+        }
+        //Repeat EHLO after STARTTLS
+        if (!$smtp->hello(gethostname())) {
+            throw new Exception('EHLO (2) failed: ' . $smtp->getError()['error']);
+        }
+        //Get new capabilities list, which will usually now include AUTH if it didn't before
+        $e = $smtp->getServerExtList();
+    }
+    //If server supports authentication, do it (even if no encryption)
+    if (array_key_exists('AUTH', $e)) {
+        if ($smtp->authenticate('username', 'password')) {
+            echo "Connected ok!";
+        } else {
+            throw new Exception('Authentication failed: ' . $smtp->getError()['error']);
+        }
+    }
 } catch (Exception $e) {
-    echo 'SMTP error: '. $e->getMessage(), "\n";
+    echo 'SMTP error: ' . $e->getMessage(), "\n";
 }
 //Whatever happened, close the connection.
 $smtp->quit(true);
diff --git a/get_oauth_token.php b/get_oauth_token.php
index e9192067..4b58138c 100644
--- a/get_oauth_token.php
+++ b/get_oauth_token.php
@@ -1,116 +1,154 @@
 <?php
 /**
- * PHPMailer - PHP email creation and transport class.
- * PHP Version 5.4
- * @package PHPMailer
- * @link https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
- * @author Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
- * @author Jim Jagielski (jimjag) <jimjag@gmail.com>
- * @author Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
- * @author Brent R. Matzelle (original founder)
- * @copyright 2012 - 2015 Marcus Bointon
- * @copyright 2010 - 2012 Jim Jagielski
- * @copyright 2004 - 2009 Andy Prevost
- * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
- * @note This program is distributed in the hope that it will be useful - WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE.
- */
-/**
- * Get an OAuth2 token from an OAuth2 provider.
+ * Get an OAuth2 token from Google.
  * * Install this script on your server so that it's accessible
  * as [https/http]://<yourdomain>/<folder>/get_oauth_token.php
- * e.g.: http://localhost/phpmailer/get_oauth_token.php
+ * e.g.: http://localhost/phpmail/get_oauth_token.php
  * * Ensure dependencies are installed with 'composer install'
- * * Set up an app in your Google/Yahoo/Microsoft account
+ * * Set up an app in your Google developer console
  * * Set the script address as the app's redirect URL
- * If no refresh token is obtained when running this file,
- * revoke access to your app and run the script again.
+ * If no refresh token is obtained when running this file, revoke access to your app
+ * using link: https://accounts.google.com/b/0/IssuedAuthSubTokens and run the script again.
+ * This script requires PHP 5.5 or later
+ * PHP Version 5.5
  */
 
-namespace PHPMailer\PHPMailer;
-
-// Aliases for League Provider Classes that may be used
-// Make sure you have added these to your composer.json and run `composer install`
-use League\OAuth2\Client\Provider\Google;
-use Hayageek\OAuth2\Client\Provider\Yahoo;
-use Stevenmaguire\OAuth2\Client\Provider\Microsoft;
-
-if (!isset($_GET['code']) && !isset($_GET['provider'])) {
-?>
-<html>
-<body>Select Provider:<br/>
-<a href='?provider=Google'>Google</a><br/>
-<a href='?provider=Yahoo'>Yahoo</a><br/>
-<a href='?provider=Microsoft'>Microsoft/Outlook/Hotmail/Live/Office365</a><br/>
-</body>
-<?php
-exit;
-}
+namespace League\OAuth2\Client\Provider;
 
 require 'vendor/autoload.php';
 
+use League\OAuth2\Client\Provider\Exception\IdentityProviderException;
+use League\OAuth2\Client\Token\AccessToken;
+use League\OAuth2\Client\Tool\BearerAuthorizationTrait;
+use Psr\Http\Message\ResponseInterface;
+
 session_start();
 
-$providerName = '';
-
-if (array_key_exists('provider', $_GET)) {
-    $providerName = $_GET['provider'];
-    $_SESSION['provider'] = $providerName;
-} elseif (array_key_exists('provider', $_SESSION)) {
-    $providerName = $_SESSION['provider'];
-}
-if (!in_array($providerName, ['Google', 'Microsoft', 'Yahoo'])) {
-    exit('Only Google, Microsoft and Yahoo OAuth2 providers are currently supported in this script.');
-}
+//If this automatic URL doesn't work, set it yourself manually
+$redirectUri = isset($_SERVER['HTTPS']) ? 'https://' : 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'];
+//$redirectUri = 'http://localhost/phpmailer/get_oauth_token.php';
 
 //These details obtained are by setting up app in Google developer console.
 $clientId = 'RANDOMCHARS-----duv1n2.apps.googleusercontent.com';
 $clientSecret = 'RANDOMCHARS-----lGyjPcRtvP';
 
-//If this automatic URL doesn't work, set it yourself manually
-$redirectUri = isset($_SERVER['HTTPS']) ? 'https://' : 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'];
-//$redirectUri = 'http://localhost/PHPMailer/redirect';
+class Google extends AbstractProvider
+{
+    use BearerAuthorizationTrait;
 
-$params = [
-    'clientId' => $clientId,
-    'clientSecret' => $clientSecret,
-    'redirectUri' => $redirectUri,
-    'accessType' => 'offline'
-];
+    const ACCESS_TOKEN_RESOURCE_OWNER_ID = 'id';
 
-$options = [];
+    /**
+     * @var string If set, this will be sent to google as the "access_type" parameter.
+     * @link https://developers.google.com/accounts/docs/OAuth2WebServer#offline
+     */
+    protected $accessType;
 
-switch ($providerName) {
-    case 'Google':
-        $provider = new Google($params);
-        $options = [
-            'scope' => [
-                'https://mail.google.com/'
-            ]
+    /**
+     * @var string If set, this will be sent to google as the "hd" parameter.
+     * @link https://developers.google.com/accounts/docs/OAuth2Login#hd-param
+     */
+    protected $hostedDomain;
+
+    /**
+     * @var string If set, this will be sent to google as the "scope" parameter.
+     * @link https://developers.google.com/gmail/api/auth/scopes
+     */
+    protected $scope;
+
+    public function getBaseAuthorizationUrl()
+    {
+        return 'https://accounts.google.com/o/oauth2/auth';
+    }
+
+    public function getBaseAccessTokenUrl(array $params)
+    {
+        return 'https://accounts.google.com/o/oauth2/token';
+    }
+
+    public function getResourceOwnerDetailsUrl(AccessToken $token)
+    {
+	return ' ';
+    }
+
+    protected function getAuthorizationParameters(array $options)
+    {
+	if (is_array($this->scope)) {
+            $separator = $this->getScopeSeparator();
+            $this->scope = implode($separator, $this->scope);
+        }
+
+        $params = array_merge(
+            parent::getAuthorizationParameters($options),
+            array_filter([
+                'hd'          => $this->hostedDomain,
+                'access_type' => $this->accessType,
+		'scope'       => $this->scope,
+                // if the user is logged in with more than one account ask which one to use for the login!
+                'authuser'    => '-1'
+            ])
+        );
+        return $params;
+    }
+
+    protected function getDefaultScopes()
+    {
+        return [
+            'email',
+            'openid',
+            'profile',
         ];
-        break;
-    case 'Yahoo':
-        $provider = new Yahoo($params);
-        break;
-    case 'Microsoft':
-        $provider = new Microsoft($params);
-        break;
+    }
+
+    protected function getScopeSeparator()
+    {
+        return ' ';
+    }
+
+    protected function checkResponse(ResponseInterface $response, $data)
+    {
+        if (!empty($data['error'])) {
+            $code  = 0;
+            $error = $data['error'];
+
+            if (is_array($error)) {
+                $code  = $error['code'];
+                $error = $error['message'];
+            }
+
+            throw new IdentityProviderException($error, $code, $data);
+        }
+    }
+
+    protected function createResourceOwner(array $response, AccessToken $token)
+    {
+        return new GoogleUser($response);
+    }
 }
 
+
+//Set Redirect URI in Developer Console as [https/http]://<yourdomain>/<folder>/get_oauth_token.php
+$provider = new Google(
+    array(
+        'clientId' => $clientId,
+        'clientSecret' => $clientSecret,
+        'redirectUri' => $redirectUri,
+        'scope' => array('https://mail.google.com/'),
+	'accessType' => 'offline'
+    )
+);
+
 if (!isset($_GET['code'])) {
     // If we don't have an authorization code then get one
-    $authUrl = $provider->getAuthorizationUrl($options);
+    $authUrl = $provider->getAuthorizationUrl();
     $_SESSION['oauth2state'] = $provider->getState();
     header('Location: ' . $authUrl);
     exit;
 // Check given state against previously stored one to mitigate CSRF attack
 } elseif (empty($_GET['state']) || ($_GET['state'] !== $_SESSION['oauth2state'])) {
     unset($_SESSION['oauth2state']);
-    unset($_SESSION['provider']);
     exit('Invalid state');
 } else {
-    unset($_SESSION['provider']);
     // Try to get an access token (using the authorization code grant)
     $token = $provider->getAccessToken(
         'authorization_code',
@@ -118,7 +156,7 @@ if (!isset($_GET['code'])) {
             'code' => $_GET['code']
         ]
     );
-    // Use this to interact with an API on the users behalf
+
     // Use this to get a new access token if the old one expires
     echo 'Refresh Token: ' . $token->getRefreshToken();
 }
diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 662eb4ad..b490432b 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -1,7 +1,7 @@
 <?php
 /**
  * PHPMailer - PHP email creation and transport class.
- * PHP Version 5.4
+ * PHP Version 5.5
  * @package PHPMailer
  * @link https://github.com/PHPMailer/PHPMailer/ The PHPMailer GitHub project
  * @author Marcus Bointon (Synchro/coolbru) <phpmailer@synchromedia.co.uk>
@@ -323,6 +323,7 @@ class PHPMailer
     /**
      * Whether to split multiple to addresses into multiple messages
      * or send them all in one message.
+     * Only supported in `mail` and `sendmail` transports, not in SMTP.
      * @var boolean
      */
     public $SingleTo = false;
@@ -578,7 +579,7 @@ class PHPMailer
     /**
      * The PHPMailer Version number.
      */
-    const VERSION = '5.4.0';
+    const VERSION = '5.5.0';
 
     /**
      * Error severity: message only, continue processing.
@@ -621,9 +622,7 @@ class PHPMailer
     public function __destruct()
     {
         //Close any open SMTP connection nicely
-        if ($this->Mailer == 'smtp') {
-            $this->smtpClose();
-        }
+        $this->smtpClose();
     }
 
     /**
@@ -1601,7 +1600,7 @@ class PHPMailer
      */
     public function smtpClose()
     {
-        if ($this->smtp !== null) {
+        if (!is_null($this->smtp)) {
             if ($this->smtp->connected()) {
                 $this->smtp->quit();
                 $this->smtp->close();
diff --git a/src/POP3.php b/src/POP3.php
index 97ca7cbe..dcfb0526 100644
--- a/src/POP3.php
+++ b/src/POP3.php
@@ -36,7 +36,7 @@ class POP3
      * @var string
      * @access public
      */
-    public $Version = '5.4.0';
+    public $Version = '5.5.0';
 
     /**
      * Default POP3 port number.
diff --git a/src/SMTP.php b/src/SMTP.php
index 730ded67..7cf98caa 100644
--- a/src/SMTP.php
+++ b/src/SMTP.php
@@ -8,7 +8,7 @@
  * @author Jim Jagielski (jimjag) <jimjag@gmail.com>
  * @author Andy Prevost (codeworxtech) <codeworxtech@users.sourceforge.net>
  * @author Brent R. Matzelle (original founder)
- * @copyright 2012 - 2015 Marcus Bointon
+ * @copyright 2012 - 2016 Marcus Bointon
  * @copyright 2010 - 2012 Jim Jagielski
  * @copyright 2004 - 2009 Andy Prevost
  * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
@@ -32,7 +32,7 @@ class SMTP
      * The PHPMailer SMTP version number.
      * @var string
      */
-    const VERSION = '5.4.0';
+    const VERSION = '5.5.0';
 
     /**
      * SMTP line break constant.
@@ -661,7 +661,7 @@ class SMTP
     protected function parseHelloFields($type)
     {
         $this->server_caps = [];
-        $lines = explode("\n", $this->last_reply);
+        $lines = explode("\n", $this->helo_rply);
 
         foreach ($lines as $n => $s) {
             //First 4 chars contain response code followed by - or space
diff --git a/test/phpmailerLangTest.php b/test/phpmailerLangTest.php
index 22d460c6..c4858f57 100644
--- a/test/phpmailerLangTest.php
+++ b/test/phpmailerLangTest.php
@@ -2,8 +2,7 @@
 /**
  * PHPMailer - language file tests
  *
- * PHP version 5.4.0
- *
+ * PHP version 5.5.0
  * @package PHPMailer
  * @author Marcus Bointon <phpmailer@synchromedia.co.uk>
  * @author Andy Prevost
diff --git a/test/phpmailerTest.php b/test/phpmailerTest.php
index af8d02b5..79597272 100644
--- a/test/phpmailerTest.php
+++ b/test/phpmailerTest.php
@@ -2,7 +2,7 @@
 /**
  * PHPMailer - PHP email transport unit tests.
  *
- * PHP version 5.4.0
+ * PHP version 5.5.0
  * @package PHPMailer
  * @author Marcus Bointon <phpmailer@synchromedia.co.uk>
  * @author Andy Prevost
@@ -50,7 +50,7 @@ class PHPMailerTest extends \PHPUnit_Framework_TestCase
      * Default include path
      * @var string
      */
-    public $INCLUDE_DIR = './';
+    public $INCLUDE_DIR = '..';
 
     /**
      * PIDs of any processes we need to kill
@@ -724,7 +724,7 @@ class PHPMailerTest extends \PHPUnit_Framework_TestCase
         $this->Mail->Body = 'Here is the text body';
         $this->Mail->Subject .= ': Plain + Multiple FileAttachments';
 
-        if (!$this->Mail->addAttachment($this->INCLUDE_DIR.'/examples/images/phpmailer.png')) {
+        if (!$this->Mail->addAttachment(realpath($this->INCLUDE_DIR . '/examples/images/phpmailer.png'))) {
             $this->assertTrue(false, $this->Mail->ErrorInfo);
             return;
         }
@@ -825,7 +825,7 @@ EOT;
 
         //This file is in ISO-8859-1 charset
         //Needs to be external because this file is in UTF-8
-        $content = file_get_contents($this->INCLUDE_DIR.'/examples/contents.html');
+        $content = file_get_contents(realpath($this->INCLUDE_DIR . '/examples/contents.html'));
         // This is the string 'éèîüçÅñæß' in ISO-8859-1, base-64 encoded
         $check = base64_decode('6eju/OfF8ebf');
         //Make sure it really is in ISO-8859-1!
@@ -835,7 +835,7 @@ EOT;
                 "ISO-8859-1",
                 mb_detect_encoding($content, "UTF-8, ISO-8859-1, ISO-8859-15", true)
             ),
-            $this->INCLUDE_DIR.'/examples'
+            realpath($this->INCLUDE_DIR . '/examples')
         );
         $this->buildBody();
         $this->assertTrue(
@@ -899,7 +899,7 @@ EOT;
 </html>
 EOT;
         $this->Mail->addEmbeddedImage(
-            $this->INCLUDE_DIR .'/examples/images/phpmailer.png',
+            realpath($this->INCLUDE_DIR . '/examples/images/phpmailer.png'),
             'my-attach',
             'phpmailer.png',
             'base64',
@@ -935,13 +935,14 @@ EOT;
      */
     public function testMsgHTML()
     {
-        $message = file_get_contents($this->INCLUDE_DIR .'/examples/contentsutf8.html');
+        $message = file_get_contents(realpath($this->INCLUDE_DIR . '/examples/contentsutf8.html'));
         $this->Mail->CharSet = 'utf-8';
         $this->Mail->Body = '';
         $this->Mail->AltBody = '';
         //Uses internal HTML to text conversion
-        $this->Mail->msgHTML($message, $this->INCLUDE_DIR .'/examples');
+        $this->Mail->msgHTML($message, realpath($this->INCLUDE_DIR . '/examples'));
         $this->Mail->Subject .= ': msgHTML';
+        $this->Mail->addAddress('user@example.com');
 
         $this->assertNotEmpty($this->Mail->Body, 'Body not set by msgHTML');
         $this->assertNotEmpty($this->Mail->AltBody, 'AltBody not set by msgHTML');
@@ -951,7 +952,7 @@ EOT;
         $this->Mail->AltBody = '';
         $this->Mail->msgHTML(
             $message,
-            $this->INCLUDE_DIR .'/examples',
+            realpath($this->INCLUDE_DIR .'/examples'),
             function ($html) {
                 return strtoupper(strip_tags($html));
             }
@@ -972,7 +973,7 @@ EOT;
         $this->Mail->isHTML(true);
 
         if (!$this->Mail->addAttachment(
-            $this->INCLUDE_DIR . '/examples/images/phpmailer_mini.png',
+            realpath($this->INCLUDE_DIR . '/examples/images/phpmailer_mini.png'),
             'phpmailer_mini.png'
         )
         ) {
@@ -997,7 +998,7 @@ EOT;
         $this->Mail->isHTML(true);
 
         if (!$this->Mail->addStringEmbeddedImage(
-            file_get_contents($this->INCLUDE_DIR .'/examples/images/phpmailer_mini.png'),
+            file_get_contents(realpath($this->INCLUDE_DIR . '/examples/images/phpmailer_mini.png')),
             md5('phpmailer_mini.png').'@phpmailer.0',
             '', //intentionally empty name
             'base64',
@@ -1022,7 +1023,7 @@ EOT;
         $this->Mail->isHTML(true);
 
         if (!$this->Mail->addAttachment(
-            $this->INCLUDE_DIR . '/examples/images/phpmailer_mini.png',
+            realpath($this->INCLUDE_DIR . '/examples/images/phpmailer_mini.png'),
             'phpmailer_mini.png'
         )
         ) {
@@ -1030,7 +1031,11 @@ EOT;
             return;
         }
 
-        if (!$this->Mail->addAttachment($this->INCLUDE_DIR .'/examples/images/phpmailer.png', 'phpmailer.png')) {
+        if (!$this->Mail->addAttachment(
+            realpath($this->INCLUDE_DIR . '/examples/images/phpmailer.png'),
+            'phpmailer.png'
+        )
+        ) {
             $this->assertTrue(false, $this->Mail->ErrorInfo);
             return;
         }
@@ -1044,13 +1049,14 @@ EOT;
      */
     public function testEmbeddedImage()
     {
-        $this->Mail->Body = 'Embedded Image: <img alt="phpmailer" src="'.'cid:my-attach">' .
+        $this->Mail->Body = 'Embedded Image: <img alt="phpmailer" src="' .
+            'cid:my-attach">' .
             'Here is an image!';
         $this->Mail->Subject .= ': Embedded Image';
         $this->Mail->isHTML(true);
 
         if (!$this->Mail->addEmbeddedImage(
-            $this->INCLUDE_DIR .'/examples/images/phpmailer.png',
+            realpath($this->INCLUDE_DIR . '/examples/images/phpmailer.png'),
             'my-attach',
             'phpmailer.png',
             'base64',
@@ -1073,13 +1079,14 @@ EOT;
      */
     public function testMultiEmbeddedImage()
     {
-        $this->Mail->Body = 'Embedded Image: <img alt="phpmailer" src="'.'cid:my-attach">' .
+        $this->Mail->Body = 'Embedded Image: <img alt="phpmailer" src="' .
+            'cid:my-attach">' .
             'Here is an image!</a>';
         $this->Mail->Subject .= ': Embedded Image + Attachment';
         $this->Mail->isHTML(true);
 
         if (!$this->Mail->addEmbeddedImage(
-            $this->INCLUDE_DIR .'/examples/images/phpmailer.png',
+            realpath($this->INCLUDE_DIR . '/examples/images/phpmailer.png'),
             'my-attach',
             'phpmailer.png',
             'base64',
@@ -1133,11 +1140,6 @@ EOT;
 
         $this->buildBody();
         $this->assertTrue($this->Mail->send(), $this->Mail->ErrorInfo);
-        if (is_writable('.')) {
-            file_put_contents('message.txt', $this->Mail->createHeader() . $this->Mail->createBody());
-        } else {
-            $this->assertTrue(false, 'Could not write local file - check permissions');
-        }
     }
 
     /**
@@ -1179,12 +1181,12 @@ EOT;
         //Only run if we have qmail installed
         if (file_exists('/var/qmail/bin/qmail-inject')) {
             $this->Mail->Body = 'Sending via qmail';
-            $this->BuildBody();
+            $this->buildBody();
             $subject = $this->Mail->Subject;
 
             $this->Mail->Subject = $subject . ': qmail';
-            $this->Mail->IsQmail();
-            $this->assertTrue($this->Mail->Send(), $this->Mail->ErrorInfo);
+            $this->Mail->isQmail();
+            $this->assertTrue($this->Mail->send(), $this->Mail->ErrorInfo);
         } else {
             $this->markTestSkipped('Qmail is not installed');
         }
@@ -1567,8 +1569,8 @@ EOT;
             "private_key_type" => OPENSSL_KEYTYPE_RSA,
         ];
         $password = 'password';
-        $certfile = 'certfile.txt';
-        $keyfile = 'keyfile.txt';
+        $certfile = 'certfile.pem';
+        $keyfile = 'keyfile.pem';
 
         //Make a new key pair
         $pk = openssl_pkey_new($keyconfig);
@@ -1992,7 +1994,8 @@ EOT;
     {
         //Start a fake POP server
         $pid = shell_exec(
-            '/usr/bin/nohup ' . $this->INCLUDE_DIR .
+            '/usr/bin/nohup ' .
+            $this->INCLUDE_DIR .
             '/test/runfakepopserver.sh 1100 >/dev/null 2>/dev/null & printf "%u" $!'
         );
         $this->pids[] = $pid;
@@ -2009,8 +2012,8 @@ EOT;
     }
 
     /**
-     * Use a fake POP3 server to test POP-before-SMTP auth.
-     * With a known-bad login
+     * Use a fake POP3 server to test POP-before-SMTP auth
+     * with a known-bad login.
      * @group pop3
      */
     public function testPopBeforeSmtpBad()
@@ -2018,7 +2021,8 @@ EOT;
         //Start a fake POP server on a different port
         //so we don't inadvertently connect to the previous instance
         $pid = shell_exec(
-            '/usr/bin/nohup '. $this->INCLUDE_DIR .
+            '/usr/bin/nohup ' .
+            $this->INCLUDE_DIR .
             '/test/runfakepopserver.sh 1101 >/dev/null 2>/dev/null & printf "%u" $!'
         );
         $this->pids[] = $pid;