Ticket #6697: bug6697.2.patch

wp-includes/formatting.php

@@ -702 +702 @@
         $title = preg_replace('/\s+/', '-', $title);
         $title = preg_replace('|-+|', '-', $title);
         $title = trim($title, '-');
+        // Use uppercase hex digits in URI-escaped characters
+        $title = preg_replace_callback( '/%[a-f0-9][a-f0-9]/',
+                                                                        create_function( '$m', 'return strtoupper( $m[0] );' ),
+                                                                        $title );
 
         return $title;
 }