stackabletech · siegfriedweber · Sep 28, 2026 · Sep 28, 2026 · Sep 28, 2026 · Sep 28, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,7 @@ All notable changes to this project will be documented in this file.
 
 - Support floating tags for product images via the new `spec.image.stackableVersionPolicy` field
   ([#186]).
+- Add support for OpenSearch 3.8.0, deprecate 3.6.0 and remove support for 3.4.0 ([#189]).
 
 ### Changed
 
@@ -36,6 +37,7 @@ All notable changes to this project will be documented in this file.
 [#172]: https://github.com/stackabletech/opensearch-operator/pull/172
 [#179]: https://github.com/stackabletech/opensearch-operator/pull/179
 [#186]: https://github.com/stackabletech/opensearch-operator/pull/186
+[#189]: https://github.com/stackabletech/opensearch-operator/pull/189
 
 ## [26.7.0] - 2026-07-21
 

diff --git a/docs/modules/opensearch/examples/getting_started/getting_started.sh b/docs/modules/opensearch/examples/getting_started/getting_started.sh
@@ -142,7 +142,7 @@ kubectl create secret generic opensearch-credentials \
 # Hide notes because they are very confusing in combination with the port forward below.
 helm install opensearch-dashboards opensearch-dashboards \
     --repo https://opensearch-project.github.io/helm-charts \
-    --version 3.6.0 \
+    --version 3.8.0 \
     --values opensearch-dashboards-values.yaml \
     --hide-notes \
     --wait

diff --git a/docs/modules/opensearch/examples/getting_started/getting_started.sh.j2 b/docs/modules/opensearch/examples/getting_started/getting_started.sh.j2
@@ -142,7 +142,7 @@ kubectl create secret generic opensearch-credentials \
 # Hide notes because they are very confusing in combination with the port forward below.
 helm install opensearch-dashboards opensearch-dashboards \
     --repo https://opensearch-project.github.io/helm-charts \
-    --version 3.6.0 \
+    --version 3.8.0 \
     --values opensearch-dashboards-values.yaml \
     --hide-notes \
     --wait

diff --git a/docs/modules/opensearch/examples/getting_started/opensearch-dashboards-values.yaml b/docs/modules/opensearch/examples/getting_started/opensearch-dashboards-values.yaml
@@ -1,7 +1,7 @@
 ---
 image:
   repository: oci.stackable.tech/sdp/opensearch-dashboards
-  tag: 3.6.0-stackable0.0.0-dev
+  tag: 3.8.0-stackable0.0.0-dev
 serviceAccount:
   create: false
   name: simple-opensearch-serviceaccount
@@ -23,6 +23,11 @@ config:
         secure: true
 # See https://github.com/opensearch-project/helm-charts/blob/main/charts/opensearch-dashboards/templates/deployment.yaml#L122
 opensearchHosts: ""
+resources:
+  requests:
+    cpu: 500m
+  limits:
+    cpu: "1"
 extraEnvs:
 - name: OPENSEARCH_HOSTS
   valueFrom:

diff --git a/docs/modules/opensearch/examples/getting_started/opensearch-dashboards-values.yaml.j2 b/docs/modules/opensearch/examples/getting_started/opensearch-dashboards-values.yaml.j2
@@ -1,7 +1,7 @@
 ---
 image:
   repository: oci.stackable.tech/sdp/opensearch-dashboards
-  tag: 3.6.0-stackable{{ versions.opensearch }}
+  tag: 3.8.0-stackable{{ versions.opensearch }}
 serviceAccount:
   create: false
   name: simple-opensearch-serviceaccount
@@ -23,6 +23,11 @@ config:
         secure: true
 # See https://github.com/opensearch-project/helm-charts/blob/main/charts/opensearch-dashboards/templates/deployment.yaml#L122
 opensearchHosts: ""
+resources:
+  requests:
+    cpu: 500m
+  limits:
+    cpu: "1"
 extraEnvs:
 - name: OPENSEARCH_HOSTS
   valueFrom:

diff --git a/docs/modules/opensearch/examples/getting_started/opensearch.yaml b/docs/modules/opensearch/examples/getting_started/opensearch.yaml
@@ -5,7 +5,7 @@ metadata:
   name: simple-opensearch
 spec:
   image:
-    productVersion: 3.6.0
+    productVersion: 3.8.0
   clusterConfig:
     security:
       settings:

diff --git a/docs/modules/opensearch/pages/usage-guide/opensearch-dashboards.adoc b/docs/modules/opensearch/pages/usage-guide/opensearch-dashboards.adoc
@@ -13,7 +13,7 @@ A basic `values.yaml` file to deploy OpenSearch Dashboards with this chart might
 opensearchHosts: null # <1>
 image: # <2>
   repository: oci.stackable.tech/sdp/opensearch-dashboards
-  tag: 3.6.0-stackable0.0.0-dev
+  tag: 3.8.0-stackable0.0.0-dev
 serviceAccount:
   create: false
   name: opensearch-serviceaccount # <3>
@@ -92,7 +92,7 @@ After the values are adjusted according to your deployment, especially `opensear
 ----
 helm install opensearch-dashboards opensearch-dashboards \
     --repo https://opensearch-project.github.io/helm-charts \
-    --version 3.6.0 \
+    --version 3.8.0 \
     --values opensearch-dashboards-values.yaml \
     --wait
 ----
diff --git a/docs/modules/opensearch/pages/usage-guide/opensearch-dashboards.adoc.j2 b/docs/modules/opensearch/pages/usage-guide/opensearch-dashboards.adoc.j2
@@ -13,7 +13,7 @@ A basic `values.yaml` file to deploy OpenSearch Dashboards with this chart might
 opensearchHosts: null # <1>
 image: # <2>
   repository: oci.stackable.tech/sdp/opensearch-dashboards
-  tag: 3.6.0-stackable{{ versions.opensearch }}
+  tag: 3.8.0-stackable{{ versions.opensearch }}
 serviceAccount:
   create: false
   name: opensearch-serviceaccount # <3>
@@ -92,7 +92,7 @@ After the values are adjusted according to your deployment, especially `opensear
 ----
 helm install opensearch-dashboards opensearch-dashboards \
     --repo https://opensearch-project.github.io/helm-charts \
-    --version 3.6.0 \
+    --version 3.8.0 \
     --values opensearch-dashboards-values.yaml \
     --wait
 ----
diff --git a/docs/modules/opensearch/pages/usage-guide/security.adoc b/docs/modules/opensearch/pages/usage-guide/security.adoc
@@ -163,7 +163,7 @@ metadata:
   name: opensearch
 spec:
   image:
-    productVersion: 3.6.0
+    productVersion: 3.8.0
   clusterConfig:
     tls:
       serverSecretClass: tls # <1>

diff --git a/docs/modules/opensearch/partials/supported-versions.adoc b/docs/modules/opensearch/partials/supported-versions.adoc
@@ -3,5 +3,5 @@
 // Stackable Platform documentation.
 
 - 3.1.0 (LTS)
-- 3.6.0
-- 3.4.0 (deprecated)
+- 3.8.0
+- 3.6.0 (deprecated)
diff --git a/rust/operator-binary/src/controller.rs b/rust/operator-binary/src/controller.rs
@@ -610,14 +610,14 @@ mod tests {
     fn validated_cluster() -> ValidatedCluster {
         ValidatedCluster::new(
             ResolvedProductImage {
-                product_version: "3.6.0".to_owned(),
-                app_version_label_value: LabelValue::from_str("3.6.0-stackable0.0.0-dev")
+                product_version: "3.8.0".to_owned(),
+                app_version_label_value: LabelValue::from_str("3.8.0-stackable0.0.0-dev")
                     .expect("should be a valid label value"),
-                image: "oci.stackable.tech/sdp/opensearch:3.6.0-stackable0.0.0-dev".to_string(),
+                image: "oci.stackable.tech/sdp/opensearch:3.8.0-stackable0.0.0-dev".to_string(),
                 image_pull_policy: "Always".to_owned(),
                 pull_secrets: None,
             },
-            ProductVersion::from_str_unsafe("3.6.0"),
+            ProductVersion::from_str_unsafe("3.8.0"),
             ClusterName::from_str_unsafe("my-opensearch"),
             NamespaceName::from_str_unsafe("default"),
             uuid!("e6ac237d-a6d4-43a1-8135-f36506110912"),

diff --git a/rust/operator-binary/src/controller/build.rs b/rust/operator-binary/src/controller/build.rs
@@ -177,14 +177,14 @@ mod tests {
     fn validated_cluster() -> ValidatedCluster {
         ValidatedCluster::new(
             ResolvedProductImage {
-                product_version: "3.6.0".to_owned(),
-                app_version_label_value: LabelValue::from_str("3.6.0-stackable0.0.0-dev")
+                product_version: "3.8.0".to_owned(),
+                app_version_label_value: LabelValue::from_str("3.8.0-stackable0.0.0-dev")
                     .expect("should be a valid label value"),
-                image: "oci.stackable.tech/sdp/opensearch:3.6.0-stackable0.0.0-dev".to_string(),
+                image: "oci.stackable.tech/sdp/opensearch:3.8.0-stackable0.0.0-dev".to_string(),
                 image_pull_policy: "Always".to_owned(),
                 pull_secrets: None,
             },
-            ProductVersion::from_str_unsafe("3.6.0"),
+            ProductVersion::from_str_unsafe("3.8.0"),
             ClusterName::from_str_unsafe("my-opensearch"),
             NamespaceName::from_str_unsafe("default"),
             uuid!("e6ac237d-a6d4-43a1-8135-f36506110912"),

diff --git a/rust/operator-binary/src/controller/build/node_config.rs b/rust/operator-binary/src/controller/build/node_config.rs
@@ -74,7 +74,7 @@ const CONFIG_OPTION_NODE_ROLES: &str = "node.roles";
 
 /// Defines the path for the logs
 /// OpenSearch grants the required access rights, see
-/// <https://github.com/opensearch-project/OpenSearch/blob/3.6.0/server/src/main/java/org/opensearch/bootstrap/Security.java#L371>
+/// <https://github.com/opensearch-project/OpenSearch/blob/3.8.0/server/src/main/java/org/opensearch/bootstrap/Security.java#L406>
 /// The permissions "write" and "delete" are required for the log file rollover.
 /// Type: string
 const CONFIG_OPTION_PATH_LOGS: &str = "path.logs";
@@ -427,7 +427,7 @@ impl NodeConfig {
     /// Please read the following sections for an explanation of these restrictions.
     ///
     /// This configuration setting replaces the setting `cluster.initial_master_nodes`, see
-    /// <https://github.com/opensearch-project/OpenSearch/blob/3.6.0/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java#L79-L93>.
+    /// <https://github.com/opensearch-project/OpenSearch/blob/3.8.0/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java#L79-L93>.
     ///
     /// This setting is required on nodes with the cluster-manager node role on a multi-node
     /// cluster. Otherwise the bootstrapping of the cluster fails and all pods report:
@@ -437,7 +437,7 @@ impl NodeConfig {
     /// error is thrown:
     ///  > setting [cluster.initial_cluster_manager_nodes] is not allowed when [discovery.type] is set to [single-node]
     ///
-    /// see <https://github.com/opensearch-project/OpenSearch/blob/3.6.0/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java#L126-L136>
+    /// see <https://github.com/opensearch-project/OpenSearch/blob/3.8.0/server/src/main/java/org/opensearch/cluster/coordination/ClusterBootstrapService.java#L126-L136>
     ///
     /// This setting does not seem to have an effect on nodes without the cluster-manager node
     /// role. However, as it is recommended (see the Elasticsearch documentation below) to not set
@@ -590,7 +590,7 @@ mod tests {
     }
 
     fn node_config(test_config: TestConfig) -> NodeConfig {
-        let image: ProductImage = serde_json::from_str(r#"{"productVersion": "3.6.0"}"#)
+        let image: ProductImage = serde_json::from_str(r#"{"productVersion": "3.8.0"}"#)
             .expect("should be a valid ProductImage");
 
         let role_group_name = RoleGroupName::from_str_unsafe("data");
@@ -659,10 +659,10 @@ mod tests {
 
         let cluster = ValidatedCluster::new(
             ResolvedProductImage {
-                product_version: "3.6.0".to_owned(),
-                app_version_label_value: LabelValue::from_str("3.6.0-stackable0.0.0-dev")
+                product_version: "3.8.0".to_owned(),
+                app_version_label_value: LabelValue::from_str("3.8.0-stackable0.0.0-dev")
                     .expect("should be a valid label value"),
-                image: "oci.stackable.tech/sdp/opensearch:3.6.0-stackable0.0.0-dev".to_string(),
+                image: "oci.stackable.tech/sdp/opensearch:3.8.0-stackable0.0.0-dev".to_string(),
                 image_pull_policy: "Always".to_owned(),
                 pull_secrets: None,
             },

diff --git a/rust/operator-binary/src/controller/build/product_logging/config.rs b/rust/operator-binary/src/controller/build/product_logging/config.rs
@@ -92,7 +92,7 @@ fn log4j2_console_appender_config(
             "PatternLayout".to_owned(),
         ),
         // Same as the default layout pattern of the console appender
-        // see https://github.com/opensearch-project/OpenSearch/blob/3.6.0/distribution/src/config/log4j2.properties#L17
+        // see https://github.com/opensearch-project/OpenSearch/blob/3.8.0/distribution/src/config/log4j2.properties#L17
         (
             "appender.CONSOLE.layout.pattern".to_owned(),
             "[%d{ISO8601}][%-5p][%-25c{1.}] [%node_name]%marker %m%n".to_owned(),

diff --git a/rust/operator-binary/src/controller/build/product_logging/test-vector.sh b/rust/operator-binary/src/controller/build/product_logging/test-vector.sh
@@ -1,5 +1,8 @@
 #!/usr/bin/env sh
 
+SUBSTITUTED_VECTOR_YAML="vector-subst.yaml"
+trap 'rm "$SUBSTITUTED_VECTOR_YAML"' EXIT
+
 DATA_DIR=/stackable/log/_vector-state \
 LOG_DIR=/stackable/log \
 OPENSEARCH_SERVER_LOG_FILE=opensearch_server.json \
@@ -9,4 +12,6 @@ ROLE_NAME=nodes \
 ROLE_GROUP_NAME=cluster-manager \
 VECTOR_AGGREGATOR_ADDRESS=vector-aggregator \
 VECTOR_FILE_LOG_LEVEL=info \
-vector test vector.yaml vector-test.yaml
+envsubst < vector.yaml > "$SUBSTITUTED_VECTOR_YAML"
+
+vector test "$SUBSTITUTED_VECTOR_YAML" vector-test.yaml
diff --git a/rust/operator-binary/src/controller/build/product_logging/vector-test.yaml b/rust/operator-binary/src/controller/build/product_logging/vector-test.yaml
@@ -1,7 +1,7 @@
 # Run tests with `./test-vector.sh`
 #
 # A downside of these test cases is that they compare the whole event and that the message can
-# contain source code positions in vector.yaml, e.g. "function call error for \"parse_timestamp\" at (990:1070)". Please adapt the tests if you change VRL code in vector.yaml.
+# contain source code positions in vector.yaml, e.g. "function call error for \"parse_timestamp\" at (999:1079)". Please adapt the tests if you change VRL code in vector.yaml.
 ---
 tests:
   - name: Test opensearch_server log entry without stacktrace
@@ -45,14 +45,14 @@ tests:
             {"type": "server", "timestamp": "2025-10-01T12:47:28,363+0000", "level": "INFO", "component": "o.o.c.c.JoinHelper", "cluster.name": "opensearch", "node.name": "opensearch-nodes-cluster-manager-0", "message": "failed to join {opensearch-nodes-cluster-manager-0}{sk-r0P_TTYuPqaamTFbjKg}{fIRSMbQYSe2nKQZ_sPn4kg}{10.244.0.20}{10.244.0.20:9300}{m}{shard_indexing_pressure_enabled=true} with JoinRequest{sourceNode={opensearch-nodes-cluster-manager-0}{sk-r0P_TTYuPqaamTFbjKg}{fIRSMbQYSe2nKQZ_sPn4kg}{10.244.0.20}{10.244.0.20:9300}{m}{shard_indexing_pressure_enabled=true}, minimumTerm=0, optionalJoin=Optional[Join{term=1, lastAcceptedTerm=0, lastAcceptedVersion=0, sourceNode={opensearch-nodes-cluster-manager-0}{sk-r0P_TTYuPqaamTFbjKg}{fIRSMbQYSe2nKQZ_sPn4kg}{10.244.0.20}{10.244.0.20:9300}{m}{shard_indexing_pressure_enabled=true}, targetNode={opensearch-nodes-cluster-manager-0}{sk-r0P_TTYuPqaamTFbjKg}{fIRSMbQYSe2nKQZ_sPn4kg}{10.244.0.20}{10.244.0.20:9300}{m}{shard_indexing_pressure_enabled=true}}]}",
             "stacktrace": ["org.opensearch.transport.RemoteTransportException: [opensearch-nodes-cluster-manager-0][10.244.0.20:9300][internal:cluster/coordination/join]",
             "Caused by: org.opensearch.cluster.coordination.CoordinationStateRejectedException: became follower",
-            "at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.lambda$$close$$3(JoinHelper.java:648) ~[opensearch-3.6.0.jar:3.6.0]",
+            "at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.lambda$$close$$3(JoinHelper.java:648) ~[opensearch-3.8.0.jar:3.8.0]",
             "at java.base/java.util.HashMap$$Values.forEach(HashMap.java:1073) ~[?:?]",
-            "at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.close(JoinHelper.java:648) ~[opensearch-3.6.0.jar:3.6.0]",
-            "at org.opensearch.cluster.coordination.Coordinator.becomeFollower(Coordinator.java:829) ~[opensearch-3.6.0.jar:3.6.0]",
-            "at org.opensearch.cluster.coordination.Coordinator.onFollowerCheckRequest(Coordinator.java:405) ~[opensearch-3.6.0.jar:3.6.0]",
-            "at org.opensearch.cluster.coordination.FollowersChecker$$2.doRun(FollowersChecker.java:250) ~[opensearch-3.6.0.jar:3.6.0]",
-            "at org.opensearch.common.util.concurrent.ThreadContext$$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975) ~[opensearch-3.6.0.jar:3.6.0]",
-            "at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52) ~[opensearch-3.6.0.jar:3.6.0]",
+            "at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.close(JoinHelper.java:648) ~[opensearch-3.8.0.jar:3.8.0]",
+            "at org.opensearch.cluster.coordination.Coordinator.becomeFollower(Coordinator.java:829) ~[opensearch-3.8.0.jar:3.8.0]",
+            "at org.opensearch.cluster.coordination.Coordinator.onFollowerCheckRequest(Coordinator.java:405) ~[opensearch-3.8.0.jar:3.8.0]",
+            "at org.opensearch.cluster.coordination.FollowersChecker$$2.doRun(FollowersChecker.java:250) ~[opensearch-3.8.0.jar:3.8.0]",
+            "at org.opensearch.common.util.concurrent.ThreadContext$$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975) ~[opensearch-3.8.0.jar:3.8.0]",
+            "at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52) ~[opensearch-3.8.0.jar:3.8.0]",
             "at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]",
             "at java.base/java.util.concurrent.ThreadPoolExecutor$$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]",
             "at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]"] }
@@ -75,14 +75,14 @@ tests:
                   \n\
                   org.opensearch.transport.RemoteTransportException: [opensearch-nodes-cluster-manager-0][10.244.0.20:9300][internal:cluster/coordination/join]\n\
                   Caused by: org.opensearch.cluster.coordination.CoordinationStateRejectedException: became follower\n\
-                  at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.lambda$$close$$3(JoinHelper.java:648) ~[opensearch-3.6.0.jar:3.6.0]\n\
+                  at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.lambda$$close$$3(JoinHelper.java:648) ~[opensearch-3.8.0.jar:3.8.0]\n\
                   at java.base/java.util.HashMap$$Values.forEach(HashMap.java:1073) ~[?:?]\n\
-                  at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.close(JoinHelper.java:648) ~[opensearch-3.6.0.jar:3.6.0]\n\
-                  at org.opensearch.cluster.coordination.Coordinator.becomeFollower(Coordinator.java:829) ~[opensearch-3.6.0.jar:3.6.0]\n\
-                  at org.opensearch.cluster.coordination.Coordinator.onFollowerCheckRequest(Coordinator.java:405) ~[opensearch-3.6.0.jar:3.6.0]\n\
-                  at org.opensearch.cluster.coordination.FollowersChecker$$2.doRun(FollowersChecker.java:250) ~[opensearch-3.6.0.jar:3.6.0]\n\
-                  at org.opensearch.common.util.concurrent.ThreadContext$$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975) ~[opensearch-3.6.0.jar:3.6.0]\n\
-                  at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52) ~[opensearch-3.6.0.jar:3.6.0]\n\
+                  at org.opensearch.cluster.coordination.JoinHelper$$CandidateJoinAccumulator.close(JoinHelper.java:648) ~[opensearch-3.8.0.jar:3.8.0]\n\
+                  at org.opensearch.cluster.coordination.Coordinator.becomeFollower(Coordinator.java:829) ~[opensearch-3.8.0.jar:3.8.0]\n\
+                  at org.opensearch.cluster.coordination.Coordinator.onFollowerCheckRequest(Coordinator.java:405) ~[opensearch-3.8.0.jar:3.8.0]\n\
+                  at org.opensearch.cluster.coordination.FollowersChecker$$2.doRun(FollowersChecker.java:250) ~[opensearch-3.8.0.jar:3.8.0]\n\
+                  at org.opensearch.common.util.concurrent.ThreadContext$$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975) ~[opensearch-3.8.0.jar:3.8.0]\n\
+                  at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52) ~[opensearch-3.8.0.jar:3.8.0]\n\
                   at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144) ~[?:?]\n\
                   at java.base/java.util.concurrent.ThreadPoolExecutor$$Worker.run(ThreadPoolExecutor.java:642) ~[?:?]\n\
                   at java.base/java.lang.Thread.run(Thread.java:1583) [?:?]",
@@ -213,7 +213,7 @@ tests:
                 "cluster": "opensearch",
                 "container": "opensearch",
                 "errors": [
-                  "Timestamp not parsable, using current time instead: function call error for \"parse_timestamp\" at (990:1070): Invalid timestamp \"unparsable\": input contains invalid characters"
+                  "Timestamp not parsable, using current time instead: function call error for \"parse_timestamp\" at (999:1079): Invalid timestamp \"unparsable\": input contains invalid characters"
                 ],
                 "file": "opensearch_server.json",
                 "level": "INFO",

diff --git a/rust/operator-binary/src/controller/build/product_logging/vector.yaml b/rust/operator-binary/src/controller/build/product_logging/vector.yaml
@@ -50,8 +50,8 @@ transforms:
 
         timestamp_string, err = string(event.timestamp)
         if err == null {
-          # OpenSearch 3.4.0 uses log4j2 2.21.0 which renders the timezone using "Z" (Zulu).
-          # OpenSearch 3.6.0 uses log4j2 2.25.0 which renders the timezone as a numeric offset (e.g. "...,122+0000").
+          # OpenSearch 3.1.0 uses log4j2 2.21.0 which renders the timezone using "Z" (Zulu).
+          # OpenSearch 3.6.0 and 3.8.0 use log4j2 2.25.x which renders the timezone as a numeric offset (e.g. "...,122+0000").
           # Try the offset format first and fall back to the literal "Z" so both layouts are parsed.
           parsed_timestamp, err = parse_timestamp(timestamp_string, "%Y-%m-%dT%H:%M:%S,%3f%z")
           if err != null {