UK Only 3D secure PSD2 SCA payments deadline

[EveryoneInvited]

Hi

With the new regulations coming in later in the UK, what will be the effect if we don't change payment providers in time for the European deadline on 1st January 2021?

The blog entry that Shopify has put forward says this:

The full enforcement of the SCA requirement in the EEA (except for the UK) is January 1, 2021. The UK regulator has extended its enforcement deadline to September 14, 2021.

What would be the difference for example if a European registered card was used on our website that wasn't compliant as opposed to a UK card? Would the UK card work normally and the EU card be declined?

Thanks for any help.

Phil