function need_upgrade() {

    /// Check requisites are passed
        if (!$this->requisitesok) {
            return COMPONENT_ERROR;
        }
    /// Get local md5
        $local_md5 = $this->get_local_md5();
    /// Get remote md5
        if (!$remote_md5 = $this->get_component_md5()) {
            return COMPONENT_ERROR;
        }
    /// Return result
       if ($local_md5 == $remote_md5) {
           return COMPONENT_UPTODATE;
       } else {
           return COMPONENT_NEEDUPDATE;
       }
    }