The /advantageAccounts endpoints on the OverDrive APIs originally returned an empty list if there were no Advantage Accounts for a LibraryID or an AdvantageAccountID. A bug was introduced that caused these enpoints to return a "null" instead. We are releasing a change today to correct that behavior. If there are no data found for the provided IDs, these endpoints will now return an HTTP 404 and a "Not Found" JSON response.
The URLs affected by this change are...
-The OverDrive API Team