--- lib/Horde/MIME/Part.php.orig	2007-09-29 23:22:47.000000000 +0800
+++ lib/Horde/MIME/Part.php	2007-10-27 15:03:11.000000000 +0800
@@ -505,6 +505,10 @@
     function getCharset()
     {
         $charset = $this->getContentTypeParameter('charset');
+        /* rafan.050209 dirty hack to big5 */
+        if (in_array(strtolower($charset), array("x-unknown", "us-ascii", "ms950", "cp950", "iso-8859-1"))) {
+            $charset = "BIG5";
+        }
         return (empty($charset)) ? null : $charset;
     }
 
--- lib/Horde/MIME.php.orig	2007-09-29 23:22:47.000000000 +0800
+++ lib/Horde/MIME.php	2007-11-02 12:51:50.000000000 +0800
@@ -133,6 +133,11 @@
         $charset = String::lower($charset);
         $line = '';
 
+	/* rafan.080106: some parts of Horde code pass UTF-8 to MIME::encode with $charset != utf-8 */
+        if (MIME::is_utf8($text) && $charset != "utf-8") {
+            $charset = "utf-8";
+        }
+
         /* Get the list of elements in the string. */
         $size = preg_match_all('/([^\s]+)([\s]*)/', $text, $matches, PREG_SET_ORDER);
 
@@ -296,6 +301,21 @@
         return $text;
     }
 
+    function is_utf8($string) {
+        return (is_string($string) && preg_match('/^.*$/us', $string));
+        /*// From http://w3.org/International/questions/qa-forms-utf-8.html
+        return preg_match('%^(?:
+              [\x09\x0A\x0D\x20-\x7E]            # ASCII
+            | [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
+            |  \xE0[\xA0-\xBF][\x80-\xBF]        # excluding overlongs
+            | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
+            |  \xED[\x80-\x9F][\x80-\xBF]        # excluding surrogates
+            |  \xF0[\x90-\xBF][\x80-\xBF]{2}     # planes 1-3
+            | [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
+            |  \xF4[\x80-\x8F][\x80-\xBF]{2}     # plane 16
+        )*$%xs', $string);*/
+    } // function is_utf8
+
     /**
      * Decodes an RFC 2047-encoded string.
      *
@@ -308,6 +328,11 @@
     function decode($string, $to_charset = null)
     {
         if (($pos = strpos($string, '=?')) === false) {
+            /* 050219.rafan: XXX subject is in RAW big5, force conversion */
+            /* 071027.rafan: force conversion from big5 only if it's not utf-8 */
+            if (!MIME::is_utf8($string)) {
+                $string = String::convertCharset($string, "big5");
+            }
             return $string;
         }
 
@@ -346,6 +371,12 @@
             $to_charset = NLS::getCharset();
         }
 
+        /* rafan.040717: dirty hack for raw 8bit subject */
+        /* rafan.050209: assume raw 8bit is BIG5 */
+        if (in_array(strtolower($charset), array("x-unknown", "us-ascii", "ms950", "cp950", "iso-8859-1"))) {
+            $charset = "BIG5";
+        }
+
         switch ($encoding) {
         case 'Q':
         case 'q':