Dual currency is the ability to view the same financial statements in each entity's local currency and in the group's currency at the same time, without recalculating or keeping two versions.
What it includes
Each entry keeps its amount in local currency and carries the amount translated at the period's consolidation exchange rate. That way the P&L, balance sheet and cash flow can be shown in either currency, and translation differences are identified instead of mixed into the result.
Example with numbers
Subsidiary in Mexico: March revenue 2,000,000 MXN, average rate 0.050: 100,000 EUR. In April it invoices 2,100,000 MXN (+5% in local currency), but the rate falls to 0.046: 96,600 EUR (−3.4% in euros). Without dual currency, the group would see a decline; with it, it sees that the subsidiary grew and the peso fell.
How Fibady does it
Each entity has its functional currency and its exchange rate per period, and the group chooses its own. The consolidation switches between local and group currency with one click, in the P&L, balance sheet and cash flow, and every translated figure opens down to the original amount in the entry.