With this iteration we keep consistency with current format of document identifiers. Auto-generated identifier is a hexadecimal string representation of binary identifier. In case of custom ID field we keep exactly the same format. This means a user has to make sure he sends document with custom ID field that follows this pattern. With the next iteration we can adjust the identifier so it doesn't require ID to be hex string.
With this iteration we keep consistency with current format of document identifiers. Auto-generated identifier is a hexadecimal string representation of binary identifier. In case of custom ID field we keep exactly the same format. This means a user has to make sure he sends document with custom ID field that follows this pattern. With the next iteration we can adjust the identifier so it doesn't require ID to be hex string.