OpenExchangeRates.org have indicated that all endpoints must have App IDs appended to the URL in order for the API to continue working. The switchover will be final very soon.
I've added the hooks for doing this and an initial test for complaining when app ids are not present. The tests will not run without an app id, which is freely obtainable.
I'll also updated the README, so it becomes obvious what needs to be done. I haven't had time to polish this as much as I'd like, but it's a decent first cut.
Added app_id necessary for ongoing usage of OER API
Tidy up formatting
+1 this commit.. today is the final day OER will work without an app id.
Merged thanks !