How to sync between 6.4 and 6.6 - Orders & Costumers

Hi All,

I have a live 6.4 shops and we are working on a 6.6 shop from zero. This was for us the best way (new hoster/other php/sql… etc)

Now we want to sync the orders and costumers between the two versions. Any suggestions how to do so? This sync does not need to be automated, manually is also ok as it is now for pre-live testing. It’s only for orders and costumers, other data is not relevant for now. In the end the plan is to sync a final time, before we go live.

Thanks,
Tim