Change: Support the new APILayer exchange rate API / drop support for CurrencyLayer API
Fix: Fix incorrect error message from the APILayer API
This version changes the currency exchange rate API, as the old one can no longer be signed up for. The link in the option has changed to the new sign-up page. The API still has a free tier that's perfectly suitable for this add-on, so there will be no cost to obtaining a new API key.
You will need to change your API key in order to continue normal operation after upgrading.