function upgraded_subscription( $type, $sub ) {

    $settings = get_post_meta( $sub->product_id, 'wpf-settings-memberpress', true );

    if ( ! empty( $settings['apply_tags_upgraded'] ) ) {
        wp_fusion()->user->apply_tags( $settings['apply_tags_upgraded'], $sub->user_id );
    }

}

add_action( 'mepr-upgraded-sub', 'upgraded_subscription', 10, 2 );