| \xF0[\x90-\xBF][\x80-\xBF]{2} # four-byte sequences 11110xxx 10xxxxxx * 3
| [\xF1-\xF3][\x80-\xBF]{3}
| \xF4[\x80-\x8F][\x80-\xBF]{2}
- ){1,50} # ...one or more times
+ ){1,40} # ...one or more times
)/x';
$location = preg_replace_callback( $regex, '_wp_sanitize_utf8_in_redirect', $location );
$location = preg_replace('|[^a-z0-9-~+_.?#=&;,/:%!*\[\]()]|i', '', $location);