In the Get Transactions for Account API, currency is not specified as a query parameter, so the
max-amount parameters are not provided with a specified currency.
Should we default the currency to AUD for these amounts?
If currency is defaulted to AUD, can we fetch only transactions performed in AUD currency?
This Standards do not define a default currency. It is at the Data Holder's discretion whether you convert the amount query parameters to AUD, or to the default currency of the account, or return all transactions within the range irrespective of currency.
If you think it reasonable, you are welcome to raise a change request to avoid ambiguity and implementation certainty.
If you choose to default to AUD or another default currency of the account, then you must convert all transactions into that default currency. You must not omit transactions.