if ( !isset( $_SESSION[ _TCM_SNS ]['upgrade_stage'] ) ) {
	return redirect( $this->_router->make_url( 'upgrade' ) );
} else if ( text2int( $_SESSION[ _TCM_SNS ]['upgrade_stage'] ) != 3 ) {
	return redirect( $this->_router->make_url( 'upgrade', 'stage'.text2int( $_SESSION[ _TCM_SNS ]['upgrade_stage'] ) );
}