diff --git a/bootstrap.php b/bootstrap.php
index 565b797..ad2684c 100644
--- a/bootstrap.php
+++ b/bootstrap.php
@@ -264,7 +264,7 @@ function imap_reopen($imap, $mailbox, $flags = 0, $retries = 0)
 if (!function_exists('imap2_reopen')) {
     function imap2_reopen($imap, $mailbox, $flags = 0, $retries = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_reopen($imap, $mailbox, $flags, $retries);
         }
 
@@ -285,7 +285,7 @@ function imap_ping($imap)
 if (!function_exists('imap2_ping')) {
     function imap2_ping($imap)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_ping($imap);
         }
 
@@ -306,7 +306,7 @@ function imap_close($imap, $flags = 0)
 if (!function_exists('imap2_close')) {
     function imap2_close($imap, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_close($imap, $flags);
         }
 
@@ -363,7 +363,7 @@ function imap_status($imap, $mailbox, $flags)
 if (!function_exists('imap2_status')) {
     function imap2_status($imap, $mailbox, $flags)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_status($imap, $mailbox, $flags);
         }
 
@@ -384,7 +384,7 @@ function imap_num_msg($imap)
 if (!function_exists('imap2_num_msg')) {
     function imap2_num_msg($imap)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_num_msg($imap);
         }
 
@@ -404,7 +404,7 @@ function imap_num_recent($imap)
 if (!function_exists('imap2_num_recent')) {
     function imap2_num_recent($imap)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_num_recent($imap);
         }
 
@@ -510,7 +510,7 @@ function imap_getmailboxes($imap, $reference, $pattern)
 if (!function_exists('imap2_getmailboxes')) {
     function imap2_getmailboxes($imap, $reference, $pattern)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_getmailboxes($imap, $reference, $pattern);
         }
 
@@ -614,7 +614,7 @@ function imap_createmailbox($imap, $mailbox)
 if (!function_exists('imap2_createmailbox')) {
     function imap2_createmailbox($imap, $mailbox)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_createmailbox($imap, $mailbox);
         }
 
@@ -634,7 +634,7 @@ function imap_create($imap, $mailbox)
 if (!function_exists('imap2_create')) {
     function imap2_create($imap, $mailbox)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_create($imap, $mailbox);
         }
 
@@ -654,7 +654,7 @@ function imap_deletemailbox($imap, $mailbox)
 if (!function_exists('imap2_deletemailbox')) {
     function imap2_deletemailbox($imap, $mailbox)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_deletemailbox($imap, $mailbox);
         }
 
@@ -706,7 +706,7 @@ function imap_mailboxmsginfo($imap)
 if (!function_exists('imap2_mailboxmsginfo')) {
     function imap2_mailboxmsginfo($imap)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_mailboxmsginfo($imap);
         }
 
@@ -726,14 +726,14 @@ function imap_search($imap, $criteria, $flags = SE_FREE, $charset = "")
 if (!function_exists('imap2_search')) {
     function imap2_search($imap, $criteria, $flags = SE_FREE, $charset = "")
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             if (empty($charset)) {
                 return imap_search($imap, $criteria, $flags);
             } else {
                 return imap_search($imap, $criteria, $flags, $charset);
             }
         }
-        
+
         return Message::search($imap, $criteria, $flags, $charset);
     }
 }
@@ -750,7 +750,7 @@ function imap_headers($imap)
 if (!function_exists('imap2_headers')) {
     function imap2_headers($imap)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_headers($imap);
         }
 
@@ -770,7 +770,7 @@ function imap_msgno($imap, $messageUid)
 if (!function_exists('imap2_msgno')) {
     function imap2_msgno($imap, $messageUid)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_msgno($imap, $messageUid);
         }
 
@@ -790,7 +790,7 @@ function imap_uid($imap, $messageNum)
 if (!function_exists('imap2_uid')) {
     function imap2_uid($imap, $messageNum)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_uid($imap, $messageNum);
         }
 
@@ -810,14 +810,14 @@ function imap_sort($imap, $criteria, $reverse, $flags = 0, $searchCriteria = nul
 if (!function_exists('imap2_sort')) {
     function imap2_sort($imap, $criteria, $reverse, $flags = 0, $searchCriteria = null, $charset = null)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             if (empty($charset)) {
                 return imap_sort($imap, $criteria, $reverse, $flags, $searchCriteria);
             } else {
                 return imap_sort($imap, $criteria, $reverse, $flags, $searchCriteria, $charset);
             }
         }
-        
+
         return Message::sort($imap, $criteria, $reverse, $flags, $searchCriteria, $charset);
     }
 }
@@ -834,7 +834,7 @@ function imap_append($imap, $folder, $message, $options = null, $internalDate =
 if (!function_exists('imap2_append')) {
     function imap2_append($imap, $folder, $message, $options = null, $internalDate = null)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_append($imap, $folder, $message, $options, $internalDate);
         }
 
@@ -854,8 +854,8 @@ function imap_headerinfo($imap, $messageNum, $fromLength = 0, $subjectLength = 0
 if (!function_exists('imap2_headerinfo')) {
     function imap2_headerinfo($imap, $messageNum, $fromLength = 0, $subjectLength = 0, $defaultHost = null)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
-            return imap_headerinfo($imap, $messageNum, $fromLength, $subjectLength, $defaultHost);
+        if (Functions::isRetrofitConnection($imap)) {
+            return imap_headerinfo($imap, $messageNum, $fromLength, $subjectLength);
         }
 
         return Message::headerInfo($imap, $messageNum, $fromLength, $subjectLength, $defaultHost);
@@ -890,7 +890,7 @@ function imap_body($imap, $messageNum, $flags = 0)
 if (!function_exists('imap2_body')) {
     function imap2_body($imap, $messageNum, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_body($imap, $messageNum, $flags);
         }
 
@@ -910,7 +910,7 @@ function imap_fetchtext($imap, $messageNum, $flags = 0)
 if (!function_exists('imap2_fetchtext')) {
     function imap2_fetchtext($imap, $messageNum, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_fetchtext($imap, $messageNum, $flags);
         }
 
@@ -930,7 +930,7 @@ function imap_fetchbody($imap, $messageNum, $section, $flags = 0)
 if (!function_exists('imap2_fetchbody')) {
     function imap2_fetchbody($imap, $messageNum, $section, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_fetchbody($imap, $messageNum, $section, $flags);
         }
 
@@ -950,7 +950,7 @@ function imap_bodystruct($imap, $messageNum, $section)
 if (!function_exists('imap2_bodystruct')) {
     function imap2_bodystruct($imap, $messageNum, $section)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_bodystruct($imap, $messageNum, $section);
         }
 
@@ -970,7 +970,7 @@ function imap_savebody($imap, $file, $messageNum, $section = "", $flags = 0)
 if (!function_exists('imap2_savebody')) {
     function imap2_savebody($imap, $file, $messageNum, $section = "", $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && Functions::isRetrofitResource($imap)) {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_savebody($imap, $file, $messageNum, $section, $flags);
         }
 
@@ -990,7 +990,7 @@ function imap_fetchstructure($imap, $messageNum, $flags = 0)
 if (!function_exists('imap2_fetchstructure')) {
     function imap2_fetchstructure($imap, $messageNum, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_fetchstructure($imap, $messageNum, $flags);
         }
 
@@ -1010,7 +1010,7 @@ function imap_fetchheader($imap, $messageNum, $flags = 0)
 if (!function_exists('imap2_fetchheader')) {
     function imap2_fetchheader($imap, $messageNum, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_fetchheader($imap, $messageNum, $flags);
         }
 
@@ -1030,7 +1030,7 @@ function imap_fetch_overview($imap, $sequence, $flags = 0)
 if (!function_exists('imap2_fetch_overview')) {
     function imap2_fetch_overview($imap, $sequence, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
            return imap_fetch_overview($imap, $sequence, $flags);
         }
 
@@ -1050,7 +1050,7 @@ function imap_fetchmime($imap, $messageNum, $section, $flags = 0)
 if (!function_exists('imap2_fetchmime')) {
     function imap2_fetchmime($imap, $messageNum, $section, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_fetchmime($imap, $messageNum, $section, $flags);
         }
 
@@ -1070,7 +1070,7 @@ function imap_delete($imap, $messageNums, $flags = 0)
 if (!function_exists('imap2_delete')) {
     function imap2_delete($imap, $messageNums, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_delete($imap, $messageNums, $flags);
         }
 
@@ -1090,7 +1090,7 @@ function imap_undelete($imap, $messageNums, $flags = 0)
 if (!function_exists('imap2_undelete')) {
     function imap2_undelete($imap, $messageNums, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_undelete($imap, $messageNums, $flags);
         }
 
@@ -1110,7 +1110,7 @@ function imap_clearflag_full($imap, $sequence, $flag, $options = 0)
 if (!function_exists('imap2_clearflag_full')) {
     function imap2_clearflag_full($imap, $sequence, $flag, $options = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_clearflag_full($imap, $sequence, $flag, $options);
         }
 
@@ -1130,7 +1130,7 @@ function imap_setflag_full($imap, $sequence, $flag, $options = 0)
 if (!function_exists('imap2_setflag_full')) {
     function imap2_setflag_full($imap, $sequence, $flag, $options = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_setflag_full($imap, $sequence, $flag, $options);
         }
 
@@ -1166,7 +1166,7 @@ function imap_mail_copy($imap, $messageNums, $mailbox, $flags = 0)
 if (!function_exists('imap2_mail_copy')) {
     function imap2_mail_copy($imap, $messageNums, $mailbox, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_mail_copy($imap, $messageNums, $mailbox, $flags);
         }
 
@@ -1186,7 +1186,7 @@ function imap_mail_move($imap, $messageNums, $mailbox, $flags = 0)
 if (!function_exists('imap2_mail_move')) {
     function imap2_mail_move($imap, $messageNums, $mailbox, $flags = 0)
     {
-        if (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        if (Functions::isRetrofitConnection($imap)) {
             return imap_mail_move($imap, $messageNums, $mailbox, $flags);
         }
 
diff --git a/src/Connection.php b/src/Connection.php
index 1a5f874..6b05a5b 100644
--- a/src/Connection.php
+++ b/src/Connection.php
@@ -143,6 +143,11 @@ protected function connect()
 
         if (empty($this->currentMailbox)) {
             $mailboxes = $this->client->listMailboxes('', '*');
+
+			if ($mailboxes === false) {
+				return false;
+			}
+
             if (in_array('INBOX', $mailboxes)) {
                 $this->currentMailbox = 'INBOX';
                 $this->mailbox .= 'INBOX';
diff --git a/src/Functions.php b/src/Functions.php
index 458dd73..0069536 100644
--- a/src/Functions.php
+++ b/src/Functions.php
@@ -105,7 +105,7 @@ public static function writeAddressFromEnvelope($addressList)
 
         $sanitizedAddress = [];
         foreach ($addressList as $addressEntry) {
-            $parsedAddressEntry = imap_rfc822_write_address($addressEntry[2], $addressEntry[3], $addressEntry[0]);
+            $parsedAddressEntry = imap_rfc822_write_address($addressEntry[2], $addressEntry[3], $addressEntry[0] ?? '');
             if (substr($parsedAddressEntry, -3) == '@""') {
                 $parsedAddressEntry = substr($parsedAddressEntry, 0, strlen($parsedAddressEntry) - 3).': ';
             }
@@ -151,9 +151,8 @@ public static function getListAttributesValue($attributes)
         return $attributesValue;
     }
 
-    public static function isValidImap1Connection($imap)
-    {
-        return is_resource($imap) && get_resource_type($imap) == 'imap';
+    public static function isValidImap1Connection($imap) {
+	    return (is_resource($imap) && get_resource_type($imap) == 'imap') || is_a($imap, 'IMAP\Connection');
     }
 
     public static function isValidImap2Connection($imap)
@@ -191,8 +190,7 @@ public static function isBackportCall($backtrace, $depth)
             && substr($backtrace[$depth + 1]['function'], 4) == substr($backtrace[$depth]['function'], 5);
     }
 
-    public static function isRetrofitResource($imap)
-    {
-        return is_resource($imap) && get_resource_type($imap) == 'imap';
+    public static function isRetrofitConnection($imap) {
+        return IMAP2_RETROFIT_MODE && self::isValidImap1Connection($imap);
     }
 }
diff --git a/src/HeaderInfo.php b/src/HeaderInfo.php
index 7784cf4..29b69d9 100644
--- a/src/HeaderInfo.php
+++ b/src/HeaderInfo.php
@@ -87,7 +87,7 @@ public static function fromMessage($message, $defaultHost)
 
     protected static function parseAddressList($address, $defaultHost)
     {
-        $addressList = imap_rfc822_parse_adrlist($address, $defaultHost);
+        $addressList = imap_rfc822_parse_adrlist($address  ?? '', $defaultHost ?? '');
         $customAddressList = [];
 
         foreach ($addressList as $objectEntry) {
diff --git a/src/Mailbox.php b/src/Mailbox.php
index c72f110..7ee072f 100644
--- a/src/Mailbox.php
+++ b/src/Mailbox.php
@@ -31,7 +31,7 @@ public static function check($imap)
                 'Recent' => intval($status['RECENT']),
             ];
 
-        } elseif (IMAP2_RETROFIT_MODE && is_resource($imap) && get_resource_type($imap) == 'imap') {
+        } elseif (Functions::isRetrofitConnection($imap)) {
             return imap_check($imap);
         }
 
diff --git a/src/Polyfill.php b/src/Polyfill.php
index 949e279..932918a 100644
--- a/src/Polyfill.php
+++ b/src/Polyfill.php
@@ -23,7 +23,7 @@ public static function convert8bit($string)
 
     public static function mimeHeaderDecode($string)
     {
-        return $string;
+	    return mb_decode_mimeheader($string);
     }
 
     public static function mutf7ToUtf8($string)
@@ -80,8 +80,13 @@ public static function rfc822ParseHeaders($headers, $defaultHost = 'UNKNOWN')
         ];
     }
 
-    public static function rfc822WriteHeaders($string)
-    {
+    public static function rfc822WriteHeaders($mailbox, $hostname, $personal) {
+		$string = $mailbox . '@' . $hostname;
+
+		if ($personal) {
+			$string = $personal . ' <'  . $string . '>';
+		}
+
         return $string;
     }
 
diff --git a/src/Roundcube/ImapClient.php b/src/Roundcube/ImapClient.php
index 6d61885..e29e413 100644
--- a/src/Roundcube/ImapClient.php
+++ b/src/Roundcube/ImapClient.php
@@ -61,6 +61,7 @@ class ImapClient
 
     protected $fp;
     protected $host;
+	protected $user;
     protected $cmd_tag;
     protected $cmd_num = 0;
     protected $resourceid;
@@ -439,8 +440,10 @@ protected function eof()
      */
     protected function closeSocket()
     {
-        @fclose($this->fp);
-        $this->fp = null;
+		if ($this->fp !== null) {
+			@fclose($this->fp);
+			$this->fp = null;
+		}
     }
 
     /**
diff --git a/src/Roundcube/MessageHeader.php b/src/Roundcube/MessageHeader.php
index 0c1201d..4276bf7 100644
--- a/src/Roundcube/MessageHeader.php
+++ b/src/Roundcube/MessageHeader.php
@@ -189,6 +189,11 @@ class MessageHeader
      */
     public $flags = array();
 
+	public $body;
+	public $modseq;
+	public $envelope;
+	public $bodypart;
+
     // map header to rcube_message_header object property
     private $obj_headers = array(
         'date'      => 'date',