diff --git a/streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/AssignorConfiguration.java b/streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/AssignorConfiguration.java
index a71c2fbb48f..c14ab700bfb 100644
--- a/streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/AssignorConfiguration.java
+++ b/streams/src/main/java/org/apache/kafka/streams/processor/internals/assignment/AssignorConfiguration.java
@@ -105,6 +105,10 @@ public final class AssignorConfiguration {
                 case StreamsConfig.UPGRADE_FROM_21:
                 case StreamsConfig.UPGRADE_FROM_22:
                 case StreamsConfig.UPGRADE_FROM_23:
+                    // ATTENTION: The following log messages is used for verification in system test
+                    // streams/streams_cooperative_rebalance_upgrade_test.py::StreamsCooperativeRebalanceUpgradeTest.test_upgrade_to_cooperative_rebalance
+                    // If you change it, please do also change the system test accordingly and
+                    // verify whether the test passes.
                     log.info("Eager rebalancing protocol is enabled now for upgrade from {}.x", upgradeFrom);
                     log.warn("The eager rebalancing protocol is deprecated and will stop being supported in a future release." +
                         " Please be prepared to remove the 'upgrade.from' config soon.");
@@ -113,6 +117,10 @@ public final class AssignorConfiguration {
                     throw new IllegalArgumentException("Unknown configuration value for parameter 'upgrade.from': " + upgradeFrom);
             }
         }
+        // ATTENTION: The following log messages is used for verification in system test
+        // streams/streams_cooperative_rebalance_upgrade_test.py::StreamsCooperativeRebalanceUpgradeTest.test_upgrade_to_cooperative_rebalance
+        // If you change it, please do also change the system test accordingly and
+        // verify whether the test passes.
         log.info("Cooperative rebalancing protocol is enabled now");
         return RebalanceProtocol.COOPERATIVE;
     }
diff --git a/tests/kafkatest/tests/streams/streams_cooperative_rebalance_upgrade_test.py b/tests/kafkatest/tests/streams/streams_cooperative_rebalance_upgrade_test.py
index 4658a532601..b4125837d5c 100644
--- a/tests/kafkatest/tests/streams/streams_cooperative_rebalance_upgrade_test.py
+++ b/tests/kafkatest/tests/streams/streams_cooperative_rebalance_upgrade_test.py
@@ -39,8 +39,8 @@ class StreamsCooperativeRebalanceUpgradeTest(Test):
     processing_message = "Processed [0-9]* records so far"
     stopped_message = "COOPERATIVE-REBALANCE-TEST-CLIENT-CLOSED"
     running_state_msg = "STREAMS in a RUNNING State"
-    cooperative_turned_off_msg = "Eager rebalancing enabled now for upgrade from %s"
-    cooperative_enabled_msg = "Cooperative rebalancing enabled now"
+    cooperative_turned_off_msg = "Eager rebalancing protocol is enabled now for upgrade from %s"
+    cooperative_enabled_msg = "Cooperative rebalancing protocol is enabled now"
     first_bounce_phase = "first_bounce_phase-"
     second_bounce_phase = "second_bounce_phase-"