Market in discount function input marked deprecated

Hi, We use the market field to make have market wise discount. We need this so that one person from the US can have 10$ off and a person from UK can have 10Pound off and match the numbers. And we also use this from blocking certain markets from using a discount.

This is marked as depreciated:
| This field will be removed in a future version of the API.

With this new change of removing the market field will make it hard for us to determine where the customer is from. Will there be something else we will be able to use?