diff --git a/CS186-proj4/pom.xml b/CS186-proj4/pom.xml
index 744a4cf..3bff337 100644
--- a/CS186-proj4/pom.xml
+++ b/CS186-proj4/pom.xml
@@ -32,7 +32,7 @@
         <dependency>
             <groupId>org.apache.mina</groupId>
             <artifactId>mina-core</artifactId>
-            <version>2.0.4</version>
+            <version>2.1.5</version>
         </dependency>
         <!-- https://mvnrepository.com/artifact/org.apache.mina/mina-filter-compression -->
         <dependency>