The problem is interesting only for users, that provide QC in more than one language. If You delete one day a language, but there is an (or more) order in this language, so it will be impossible to open this order. the call:
will fail. Maybe for the future, would not be bad to save the currency of the order into the orders-database? Beacause the currency can change soon (złoty -> eur)? And after changing in config into new currency, you will get all old orders in new currency (an order for 1000 zł yesterday will show you 1000 eur tomorrow).