Reviso is a multi-currency accounting system. When you take out a Reviso subscription in the UK the base currency will automatically be in GBP however, you can change this base currency to one of the 93 (as at Oct 21) different currencies listed.
You can also process any type of transaction in one of these currencies and when you process the entry, whether that's a sales invoice, payment or journal entry you can select the currency you wish to process in.
The exchange rate of the selected currency will appear and you can change this should you need to for one off transactions. The exchange rate that appears is driven by xe.com
You can also go the currency listing and enter a fixed rate of your choice and all transactions will then be based on that rate until you change it again.
Please note the exchange rate entered must be to the power of 100.