Match-IT is fully multi-currency capable. As installed there are predefined currencies for British Sterling, US Dollars and Euros, but you can add as many others as you wish. The system will convert between currencies as the context dictates. Currencies are usually converted by reference to an exchange rate variable. As installed there are predefined variables to convert US Dollars and Euros to British Sterling. These should be updated on a regular basis to reflect the prevailing exchange rate. To do that go to Function | Standing Data | Units... | View Variables, this will open a form that will look similar to this:

When an exchange rate changes, you can either change the existing variable's value or you can add a new one with a new effective date. The latter means you can see a history of how it's changing.

Internally, the system holds all historical currency values in British Sterling (or whatever your Stock Currency (ms) default is set to). All foreign currencies associated with supplier and customer invoices are converted to sterling and recorded when the invoices are approved, this means they are not affected by subsequent exchange rate changes.

If you add a new currency, you only have define an exchange rate between it and sterling, the system can then work out how to convert to any currency by going 'through' sterling (or whatever your Currency (um) default is set to).