diff --git a/ch06/pom.xml b/ch06/pom.xml
index 160b5ac..5c6b8e5 100644
--- a/ch06/pom.xml
+++ b/ch06/pom.xml
@@ -258,7 +258,7 @@
     <dependency>
       <groupId>com.google.protobuf</groupId>
       <artifactId>protobuf-java</artifactId>
-      <version>2.6.1</version>
+      <version>3.16.3</version>
     </dependency>
     <dependency>
       <groupId>org.apache.thrift</groupId>