Are you using the protocol_version configuration?
config :extreme, :protocol_version, 4
https://github.com/exponentially/extreme/blob/master/README.md#eventstore-v4-and-later-note
Are you using the protocol_version configuration?
config :extreme, :protocol_version, 4
https://github.com/exponentially/extreme/blob/master/README.md#eventstore-v4-and-later-note