This module allows users to update the currency manually for invoices
that are still in the draft stage. It offers flexibility to companies
when calculating currency rates for invoicing.

For example, if a company makes a deal with a vendor but the actual
purchase happens on a different day, this module lets them choose
whether to use the currency rate from the accounting date or a special
rate agreed upon during the deal. This ensures accurate currency rate
calculations for invoices, even when the purchase date and deal date
differ.
