Is Shipping Rates Calculator+ compatible with Online Store 2.0 themes?

Shipping Rates Calculator+ is totally compatible with Online Store 2.0 themes so, if you are using one of those themes in your store, the widget will be correctly displayed in the cart page providing the available shipping rates you have configured in your Shopify admin for the cart contents

Regarding the App Blocks feature, it is not supported yet. However, if you want to change the app's configuration, you can easily do it from the preferences page (How can I access the app preferences page?). There you will be able to change the widget location within your cart page, change the visual styles in order to match your theme, and add estimates if you are using real-time carriers.

Additionally, in case you don’t manage to move the app to the desired position or make the required configuration, we do offer 24/7 customer service and will be glad to help you with anything you might need.