diff --git a/program/lib/Roundcube/rcube_imap_generic.php b/program/lib/Roundcube/rcube_imap_generic.php
index 764604d6a..f682b71e1 100644
--- a/program/lib/Roundcube/rcube_imap_generic.php
+++ b/program/lib/Roundcube/rcube_imap_generic.php
@@ -1128,35 +1128,61 @@ class rcube_imap_generic
 
             $response = explode("\r\n", $response);
             foreach ($response as $line) {
-                if (preg_match('/^\* ([0-9]+) (EXISTS|RECENT)$/i', $line, $m)) {
-                    $this->data[strtoupper($m[2])] = (int) $m[1];
-                }
-                else if (preg_match('/^\* OK \[/i', $line, $match)) {
-                    $line = substr($line, 6);
-                    if (preg_match('/^(UIDNEXT|UIDVALIDITY|UNSEEN) ([0-9]+)/i', $line, $match)) {
-                        $this->data[strtoupper($match[1])] = (int) $match[2];
-                    }
-                    else if (preg_match('/^(HIGHESTMODSEQ) ([0-9]+)/i', $line, $match)) {
-                        $this->data[strtoupper($match[1])] = (string) $match[2];
-                    }
-                    else if (preg_match('/^(NOMODSEQ)/i', $line, $match)) {
-                        $this->data[strtoupper($match[1])] = true;
-                    }
-                    else if (preg_match('/^PERMANENTFLAGS \(([^\)]+)\)/iU', $line, $match)) {
-                        $this->data['PERMANENTFLAGS'] = explode(' ', $match[1]);
+                if (preg_match('/^\* OK \[/i', $line)) {
+                    $pos   = strcspn($line, ' ]', 6);
+                    $token = strtoupper(substr($line, 6, $pos));
+                    $pos   += 7;
+
+                    switch ($token) {
+                    case 'UIDNEXT':
+                    case 'UIDVALIDITY':
+                    case 'UNSEEN':
+                        if ($len = strspn($line, '0123456789', $pos)) {
+                            $this->data[$token] = (int) substr($line, $pos, $len);
+                        }
+                        break;
+
+                    case 'HIGHESTMODSEQ':
+                        if ($len = strspn($line, '0123456789', $pos)) {
+                            $this->data[$token] = (string) substr($line, $pos, $len);
+                        }
+                        break;
+
+                    case 'NOMODSEQ':
+                        $this->data[$token] = true;
+                        break;
+
+                    case 'PERMANENTFLAGS':
+                        $start = strpos($line, '(', $pos);
+                        $end   = strrpos($line, ')');
+                        if ($start && $end) {
+                            $flags = substr($line, $start + 1, $end - $start - 1);
+                            $this->data[$token] = explode(' ', $flags);
+                        }
+                        break;
                     }
                 }
-                // QRESYNC FETCH response (RFC5162)
-                else if (preg_match('/^\* ([0-9+]) FETCH/i', $line, $match)) {
-                    $line       = substr($line, strlen($match[0]));
-                    $fetch_data = $this->tokenizeResponse($line, 1);
-                    $data       = array('id' => $match[1]);
-
-                    for ($i=0, $size=count($fetch_data); $i<$size; $i+=2) {
-                        $data[strtolower($fetch_data[$i])] = $fetch_data[$i+1];
-                    }
+                else if (preg_match('/^\* ([0-9]+) (EXISTS|RECENT|FETCH)/i', $line, $match)) {
+                    $token = strtoupper($match[2]);
+                    switch ($token) {
+                    case 'EXISTS':
+                    case 'RECENT':
+                        $this->data[$token] = (int) $match[1];
+                        break;
 
-                    $this->data['QRESYNC'][$data['uid']] = $data;
+                    case 'FETCH':
+                        // QRESYNC FETCH response (RFC5162)
+                        $line       = substr($line, strlen($match[0]));
+                        $fetch_data = $this->tokenizeResponse($line, 1);
+                        $data       = array('id' => $match[1]);
+
+                        for ($i=0, $size=count($fetch_data); $i<$size; $i+=2) {
+                            $data[strtolower($fetch_data[$i])] = $fetch_data[$i+1];
+                        }
+
+                        $this->data['QRESYNC'][$data['uid']] = $data;
+                        break;
+                    }
                 }
                 // QRESYNC VANISHED response (RFC5162)
                 else if (preg_match('/^\* VANISHED [()EARLIER]*/i', $line, $match)) {