diff --git a/src/ch6/serving/tensor-serving-client-test/pom.xml b/src/ch6/serving/tensor-serving-client-test/pom.xml
index 991e36a..445ee62 100644
--- a/src/ch6/serving/tensor-serving-client-test/pom.xml
+++ b/src/ch6/serving/tensor-serving-client-test/pom.xml
@@ -40,7 +40,7 @@
 		<dependency>
 			<groupId>ch.qos.logback</groupId>
 			<artifactId>logback-core</artifactId>
-			<version>1.0.13</version>
+			<version>1.2.0</version>
 		</dependency>
 		<dependency>
 		    <groupId>io.grpc</groupId>