How many cards will be compatible with 3DSv2 by 14th September 2019?

As issuers have not provided us with reliable data yet, we don't have information on that. MasterCard is currently running surveys in Europe, but results may vary drastically depending on the country.  The status will continue to evolve until September. In January 2019, only 2/3 of issuers completed the EMVCo v2.1 certification and within this list of issuers, support of exemptions fluctuated from 80% (Recurring) to 50% (White Listing).