set default value of kafka version to 2.1.0 (#41662)

* set default value of kafka version to 2.1.0

CHANGELOG.next.asciidoc

@@ -16,6 +16,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Beats will rate limit the logs about errors when indexing events on Elasticsearch, logging a summary every 10s. The logs sent to the event log is unchanged. {issue}40157[40157]
 - Drop support for Debian 10 and upgrade statically linked glibc from 2.28 to 2.31 {pull}41402[41402]
 - Fix metrics not being ingested, due to "Limit of total fields [10000] has been exceeded while adding new fields [...]". The total fields limit has been increased to 12500. No significant performance impact on Elasticsearch is anticipated. {pull}41640[41640]
+- Set default kafka version to 2.1.0 in kafka output and filebeat. {pull}41662[41662]
 
 *Auditbeat*
 

filebeat/docs/inputs/input-kafka.asciidoc

@@ -89,7 +89,7 @@ The Kafka client id (optional).
 [float]
 ===== `version`
 
-The version of the Kafka protocol to use (defaults to `"1.0.0"`). When using Kafka 4.0 and newer, the version must be set to at least `"2.1.0"`.
+The version of the Kafka protocol to use (defaults to `"2.1.0"`). When using Kafka 4.0 and newer, the version must be set to at least `"2.1.0"`.
 
 [float]
 ===== `initial_offset`

filebeat/input/kafka/config.go

@@ -110,7 +110,7 @@ var (
 // were chosen to match sarama's defaults.
 func defaultConfig() kafkaInputConfig {
 	return kafkaInputConfig{
-		Version:        kafka.Version("1.0.0"),
+		Version:        kafka.Version("2.1.0"),
 		InitialOffset:  initialOffsetOldest,
 		ClientID:       "filebeat",
 		ConnectBackoff: 30 * time.Second,

libbeat/outputs/kafka/config.go

@@ -136,7 +136,7 @@ func defaultConfig() kafkaConfig {
 		BrokerTimeout:    10 * time.Second,
 		Compression:      "gzip",
 		CompressionLevel: 4,
-		Version:          kafka.Version("1.0.0"),
+		Version:          kafka.Version("2.1.0"),
 		MaxRetries:       3,
 		Headers:          nil,
 		Backoff: backoffConfig{

libbeat/outputs/kafka/docs/kafka.asciidoc

@@ -69,7 +69,7 @@ The cluster metadata contain the actual Kafka brokers events are published to.
 
 ===== `version`
 
-Kafka protocol version that {beatname_uc} will request when connecting. Defaults to 1.0.0. When using Kafka 4.0 and newer, the version must be set to at least `"2.1.0"`
+Kafka protocol version that {beatname_uc} will request when connecting. Defaults to 2.1.0. When using Kafka 4.0 and newer, the version must be set to at least `"2.1.0"`
 
 Valid values are all kafka releases in between `0.8.2.0` and `2.6.0`.