The changes done in KAFKA-257 result in the sink connector failing if the ErrantRecordReporter cannot be found. This may happen if Kafka Connect <2.6 is used, and according to https://docs.mongodb.com/kafka-connector/current/compatibility/#kafka-compatibility we support Kafka Connect >=2.1. robert.walters confirmed that we are going to continue supporting it in the 1.7 release of the MongoDB Kafka Connector.