In Order for you to be able to sync past orders, you’ll need to use Sync By Date Range Feature.

• 1. Go to App Dashboard and click on "Sync By Date Range".

• 2. In this second step select the starting date from which you want to sync tracking numbers of orders received in your store.

• 3. Followed by selecting the End Date up to which you want to sync tracking numbers.
  
  Note: Date range function can only sync orders up to 90 days before the App installation date.