How is determined if a transaction goes through 3DS1 or 3DS2?

If your integration is 3DS2 ready, and you are sending along the required fields, it is still possible that a transaction will end up going through 3DS1.

This is the case because not all issuing banks are ready to handle 3DS2 yet, and even if they are, some issuing banks have a worse performance on 3DS2 transactions compared to 3DS1 transactions. To overcome this, our platform observes the performance on 3DS2 transactions and if a better performance is observed for 3DS1 for a specific issuing bank we route the transaction over 3DS1.