AASB 121 The Effects of Changes in Foreign Exchange Rates 35-37: Change in functional currency: apply the new currency's procedures prospectively from when the change happens, using the rate at that date for all items, and carry forward previously recognised OCI differences until disposal

What does 35-37 require?

When underlying transactions, events and conditions change enough to alter an entity's functional currency, the procedures for the new currency apply only from that date forward. All items are translated into the new functional currency at the rate on that date, and the translated amounts of non-monetary items become their historical cost. Exchange differences from translating a foreign operation that were previously recognised in OCI are not reclassified until the operation is disposed of.