Apple Pay 3dSecure Version for Mastercard

We have finished integrating Apple Pay in our app and our payment processor is requiring us to send the 3dSecure version used for apple pay (2.1,2.2,2.3,etc.). I believe this only applies to mastercard but would appreciate if anyone has run into something similar and what you specified. I have not been able to find anything in Apple's documentation specifying the version that is used.

Apple Pay 3dSecure Version for Mastercard
 
 
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