Enhancements

• References librdkafka.redist 1.9.0. Refer to the librdkafka release notes for a complete list of changes, enhancements, fixes and upgrade considerations.
• References Apache.Avro 1.11.0. Refer to the release notes for further information (JanReimerD).
• Added support for serializing and deserializing null in Avro serdes (YairHalberstadt).
• Enhanced CachedSchemaRegistryClient to allow for user-implemented authentication schemes (henrydaly).
• Reduced memory use when producing with delivery reports disabled (TrickyCat).

Fixes

• Resolved incompatibility with Apple M1 processors (dkaukov).
• No longer crashes on Alpine Linux when MUSL is installed (shurivich).
• JSON validation exception messages now properly include failing paths (drinehimer).
• Upgraded Google.Protobuf dependency to 3.15.0 (CVE-2021-22570).
• Resolved memory leak in AdminClient response handler (emasab).
• Resolved memory leak in Producer.SendOffsetsToTransaction.

Upgrade Considerations

• The earliest supported .NET Framework version is now 4.6.2, previously this was 4.5 (bjornbouetsmith).