diff --git a/public/admin/tool/messageinbound/roundcube/rcube_utils.php b/public/admin/tool/messageinbound/roundcube/rcube_utils.php
index b9db11f0a3a..7a413ad7dee 100644
--- a/public/admin/tool/messageinbound/roundcube/rcube_utils.php
+++ b/public/admin/tool/messageinbound/roundcube/rcube_utils.php
@@ -285,6 +285,22 @@ class rcube_utils
         return is_string($value) ? $value : '';
     }
 
+    /**
+     * Check if input value is a "simple" string.
+     * "Simple" is defined as a non-empty string containing only
+     *  - "word" characters (alphanumeric plus underscore),
+     *  - dots,
+     *  - dashes.
+     *
+     * @param string $input The string to test
+     *
+     * @return bool
+     */
+    public static function is_simple_string($input)
+    {
+        return is_string($input) && !!preg_match('/^[\w.-]+$/i', $input);
+    }
+
     /**
      * Read request parameter value and convert it for internal use
      * Performs stripslashes() and charset conversion if necessary
@@ -1729,10 +1745,10 @@ class rcube_utils
 
     /**
      * Clean the subject from reply and forward prefix
-     * 
+     *
      * @param string $subject Subject to clean
      * @param string $mode Mode of cleaning : reply, forward or both
-     * 
+     *
      * @return string Cleaned subject
      */
     public static function remove_subject_prefix($subject, $mode = 'both')
diff --git a/public/admin/tool/messageinbound/thirdpartylibs.xml b/public/admin/tool/messageinbound/thirdpartylibs.xml
index d1cca847600..74fbc9468ef 100644
--- a/public/admin/tool/messageinbound/thirdpartylibs.xml
+++ b/public/admin/tool/messageinbound/thirdpartylibs.xml
@@ -5,7 +5,7 @@
         <name>Roundcube Framework</name>
         <license>GPL</license>
         <licenseversion>3.0+</licenseversion>
-        <version>1.6.10</version>
+        <version>1.6.11</version>
         <repository>https://github.com/roundcube/roundcubemail</repository>
         <copyrights>
             <copyright>The Roundcube Dev Team</copyright>