Modify texts in WooCommerce Subscription plugin

gistfile1.txt

// change the “for” to "up to for"
function change_subscription_product_string( $subscription_string, $product, $include ) {
    if( $include ){
        $subscription_string = str_replace('for', 'for up to', $subscription_string);
    }
    return $subscription_string;
}
add_filter( 'woocommerce_subscriptions_product_price_string', 'change_subscription_product_string', 10, 3 );