having a problem with the flatten value transformation - jdbc

Question

I am attempting to flatten a topic before sending it along to my postgres db, using something like the connector below. I am using the confluent 4.1.1 kafka connect docker image, the only change being I copied a custom connector jar into /usr/share/java and am running it under a different accoount.
version (kafka connect) "1.1.1-cp1"
commit "0a5db4d59ee15a47"
{
"name": "problematic_postgres_sink",
"config": {
"connector.class": "io.confluent.connect.jdbc.JdbcSinkConnector",
"key.converter": "org.apache.kafka.connect.storage.StringConverter",
"key.converter.schema.registry.url": "http://kafkaschemaregistry.service.consul:8081",
"value.converter": "io.confluent.connect.avro.AvroConverter",
"value.converter.schema.registry.url": "http://kafkaschemaregistry.service.consul:8081",
"connection.url": "jdbc:postgresql://123.123.123.123:5432/mypostgresdb",
"connection.user": "abc",
"connection.password": "xyz",
"insert.mode": "upsert",
"auto.create": true,
"auto.evolve": true,
"topics": "mytopic",
"pk.mode": "kafka",
"transforms": "Flatten",
"transforms.Flatten.type": "org.apache.kafka.connect.transforms.Flatten$Value",
"transforms.Flatten.delimiter": "_"
}
}
I get a 400 error code:
Connector configuration is invalid and contains the following 1
error(s): Invalid value class
org.apache.kafka.connect.transforms.Flatten for configuration
transforms.Flatten.type: Error getting config definition from
Transformation: null