🚨 Attention: Planned Kafka Upgrade with Client compatibility impact at 2026-05-04 or later
Maintenance
May 4, 2026 at 11:46am UTC
Dear Data Platform Users,
we are planning to upgrade from Kafka 3.9.0 to Kafka 4.0.1 in CW 19 (between 2026-05-04 and 2026-05-08). During our preliminary evaluation we came upon a long-standing bug in librdkafka < 2.6.1 that causes SASL/SCRAM authentication to fail against Kafka 4.x brokers. To avoid service disruption you need to upgrade your Kafka clients (consumers and producers) to use the new library versions. The librdkafka is used as a basis for the following clients:
| Language | Client Library | Fixed version |
|---|---|---|
| C/C++ | librdkafka | 2.6.1 (2024-11-18) |
| Python | confluent-kafka-python / confluent-kafka | 2.6.1 (2024-11-18) |
| Go | confluent-kafka-go | 2.6.1 (2024-11-18) |
| .NET | confluent-kafka-dotnet / Confluent.Kafka | 2.6.1 (2024-11-18) |
| .NET | kafkaflow / KafkaFlow | 4.0.0 (2025-04-24) |
| Rust | rdkafka-sys | 4.9.0+2.10.0 (2025-07-05?) |
| Rust | rdkafka | 0.39.0 (2026-01-25) or possibly 0.38.0 |
The following libraries do not include librdkafka and are thus (likely) not affected by the aforementioned bug. We have not tested the library versions.
| Language | Client Library |
|---|---|
| Go | Sarama |
| Go | franz-go |
| Python | kafka-python |
| Python | aiokafka |
| .NET | Microsoft.Azure.Functions.Worker.Extensions.Kafka |
Do note that you should use up-to-date library versions, to ensure compatibility with Kafka 4.0. If you want to test your business critical applications before the upgrade, please contact us.
Affected services