Via Amazon Seller Central News:
We’ve updated our Valid Tracking Rate (VTR) Help page and FAQ with new recommendations to help you improve your VTR.
Updated information includes:
Best practices to Successfully Upload Tracking Information: Learn how to reduce order-related defects by avoiding actions that can damage your shipping performance metrics, such as using unsupported carriers or confirming or updating tracking after carrier delivery scan.
Adding Tracking Information: See the list of carriers integrated with Amazon.
By providing detailed shipment tracking information, you can improve the customer delivery experience; reduce customer contacts, order-related defects, and lost-shipment costs; and improve your feedback ratings.