Katana keeps the currency rates updated daily for your open orders, but the rate is fixed in certain situations.
From business perspective, the currency rate should typically be fixed at the moment of creating a bill. Katana does not have an accounting module, but Katana will fix the currency rates on orders at the moment when you are likely to create the bill in your accounting system.
Katana will automatically fix your currency rate and date and will not anymore update the conversion rate daily when:
Purchase Order is set to "Received" or for the part that is "Partially received"
Sometimes it may still be required to manually edit the conversion rate and Katana allows you to adjust the conversion rate and date on the order - read more here.
Fixing the currency rate on the "Partially received" order
When an order is "Partially received" then the currency rate is fixed for the part that has been received. Items that have not been received still use the daily exchange rate. Receiving purchase orders partially can result in every received part having a separate currency rate as they were received at separate times.
Example of a Purchase Order with partially received items:
Billing partially received orders in foreign currency
When issuing a bill for Xero or Quickbooks Online for an order that has been partially received then Katana will adjust the conversion rate on all received parts of the order.