diff --git a/app/src/main/java/org/astraea/app/checker/Checker.java b/app/src/main/java/org/astraea/app/checker/Checker.java
index 79d0575a9..fd660685f 100644
--- a/app/src/main/java/org/astraea/app/checker/Checker.java
+++ b/app/src/main/java/org/astraea/app/checker/Checker.java
@@ -35,7 +35,7 @@
 
 public class Checker {
 
-  private static final List<Guard> GUARDS = List.of(new RpcGuard());
+  private static final List<Guard> GUARDS = List.of(new RpcGuard(), new ConfigGuard());
 
   public static void main(String[] args) throws Exception {
     execute(Argument.parse(new Argument(), args));
diff --git a/app/src/main/java/org/astraea/app/checker/Report.java b/app/src/main/java/org/astraea/app/checker/Report.java
index 8fd46469a..c6079062d 100644
--- a/app/src/main/java/org/astraea/app/checker/Report.java
+++ b/app/src/main/java/org/astraea/app/checker/Report.java
@@ -22,10 +22,6 @@
 import org.apache.kafka.common.Node;
 
 public record Report(Node node, String why) {
-  static Report noMetrics(Node node) {
-    return new Report(node, "failed to get metrics from");
-  }
-
   static Report of(Node node, String why) {
     return new Report(node, why);
   }
@@ -41,7 +37,7 @@ static Report of(Node node, Protocol protocol, Set<Integer> versions) {
     return new Report(
         node,
         String.format(
-            "there are unsupported %s versions: %s due to new baseline: %s",
+            "there are unsupported %s versions: %s and new baseline: [%s]",
             protocol.name(), unsupportedVersions, protocol.base()));
   }
 
@@ -52,9 +48,6 @@ Stream<Report> stream() {
 
   @Override
   public String toString() {
-    if (node == null) {
-      return "Report[pass]";
-    }
-    return "Report[" + node + "]  why = " + why;
+    return "[" + node + "] has issue to 4.0 because \"" + why + "\"";
   }
 }
diff --git a/app/src/main/java/org/astraea/app/checker/RpcGuard.java b/app/src/main/java/org/astraea/app/checker/RpcGuard.java
index a4394b9c7..0d2b6f32a 100644
--- a/app/src/main/java/org/astraea/app/checker/RpcGuard.java
+++ b/app/src/main/java/org/astraea/app/checker/RpcGuard.java
@@ -40,11 +40,11 @@ private Collection<Report> checkNode(
       Node node, Map<String, Protocol> protocols, Function<Node, MBeanClient> clients) {
     return Arrays.stream(NetworkMetrics.Request.values())
         .filter(request -> protocols.containsKey(request.metricName().toLowerCase()))
-        .map(
+        .flatMap(
             request -> {
               var protocol = protocols.get(request.metricName().toLowerCase());
-              var versions = NetworkMetrics.Request.PRODUCE.versions(clients.apply(node));
-              return Report.of(node, protocol, versions);
+              var versions = request.versions(clients.apply(node));
+              return Report.of(node, protocol, versions).stream();
             })
         .toList();
   }