We stream data to kafka and use SASL mechanism SCRAM-SHA-512. After upgrading kafka from v3.x to v4.0, streaming stopped working.

After some more investigations we bumped into this issue of the librdkafka library: https://github.com/confluentinc/librdkafka/pull/4895

A comment from the issue says:

Note: It seems that versions of librdkafka without this fix fails to talk to Kafka 4.0.0, which changed that endsWith to equals.

This mostly means that the minimum version of librdkafka that works with Kafka 4.0.0, when using SCRAM-based authentication, is 2.6.1, not 1.8.2. 

We are running HVR Hub 6.1.0/64 (and lower patch levels) and suspect the included librdkafka version is not high enough. 

This is rather a bug / regression than a new feature request and will become blocking for us in the near future. Thanks for looking into this!