diff --git a/.github/workflows/actions_build.yml b/.github/workflows/actions_build.yml
index 2dd109fd4..86de3a4ae 100644
--- a/.github/workflows/actions_build.yml
+++ b/.github/workflows/actions_build.yml
@@ -28,7 +28,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-12, windows-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         java: [21]
         include:
           - java: 8
diff --git a/server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java b/server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java
index 1ea949c56..b3e674221 100644
--- a/server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java
+++ b/server/src/main/java/com/linecorp/centraldogma/server/internal/replication/ZooKeeperCommandExecutor.java
@@ -83,6 +83,7 @@
 import com.github.benmanes.caffeine.cache.Caffeine;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Joiner;
+import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMultimap;
 import com.google.common.escape.Escaper;
@@ -1203,6 +1204,16 @@ List<Long> blocks() {
         public void appendBlock(long blockId) {
             blocks.add(blockId);
         }
+
+        @Override
+        public String toString() {
+            return MoreObjects.toStringHelper(this)
+                              .add("replicaId", replicaId)
+                              .add("timestamp", timestamp)
+                              .add("size", size)
+                              .add("blocks", blocks)
+                              .toString();
+        }
     }
 
     private long storeLog(ReplicationLog<?> log) {