The new Shopify App has been designed to support high levels of transactions e.g. orders, inventory updates, fulfilments etc. It also allows for a modular app giving you the option to only install and configure segments of the full app. For example if you only want to download orders and not send fulfilment status updates back to Shopify, then you can simply install the required components.
The app settings are now embedded into your Shopify store and provide a more usable experience. It is configured directly from within Shopify
There are also several actions that you can trigger through the store yourself such as downloading single orders or importing Shopify products into Brightpearl.
Note: The new app takes the place of the old app and should be a complete replacement. Please do not run both concurrently