Query on Croatia joining the EU

Experts I have a query on Croatia joining the EU

I have a client who has no operation in Croatia, no plant, there is no company code for Croatia therefore the only business they have in Croatia is Customers and Vendors.

I am after advice what should be done in SAP before Croatia is going to join the EU.

What advise should I give to my client or what changes I should recommend from SD and MM point of view?

I will really appreciate your help on this please and rewards will be given.

Regards,

Ian