seems like sarama supports any delimiter between the digits

this does appear to be true, but good catch. i just assumed that passing the supportVersion names would work, but ParseKafkaVersion actually wants the semver string. eg. 0.10.0.0

for version <1.0 it is using the regex ^0\.\d+\.\d+\.\d+$ and for >= 1.0 it is using ^\d+\.\d+\.\d+$

I notice there's a kafka release 1.1.1 for which there is no protocol version in sarama

Sarama only uses the version number to determine what Kafka features it can use. It does this with calls like

if bc.consumer.conf.Version.IsAtLeast(V0_10_0_0) {
		request.Version = 2
	}
	if bc.consumer.conf.Version.IsAtLeast(V0_10_1_0) {
		request.Version = 3
		request.MaxBytes = MaxResponseSize
	}
	if bc.consumer.conf.Version.IsAtLeast(V0_11_0_0) {
		request.Version = 4
		request.Isolation = ReadUncommitted // We don't support yet transactions.
	}

So the version provided doesn need to be in the list of supported versions.

@Dieterbe this should be good now