diff --git a/README.md b/README.md
index 29eb978..e57af10 100644
--- a/README.md
+++ b/README.md
@@ -156,7 +156,10 @@ all languages.
 
 ## Release Notes
 
-### Release 3.1.3.post2 (July 9, 2026)
+### Release 3.1.3.post4 (July 29, 2026)
+* Bump netty.version from 4.2.15.Final to 4.2.16.Final
+
+### Release 3.1.3.post3 (July 9, 2026)
 * Bump fasterxml-jackson.version from 2.18.6 to 2.18.8
 
 ### Release 3.1.3.post2 (June 22, 2026)
diff --git a/pom.xml b/pom.xml
index 3d884ed..4e2186a 100644
--- a/pom.xml
+++ b/pom.xml
@@ -4,7 +4,7 @@
     <properties>
         <awssdk.version>2.33.0</awssdk.version>
         <kcl.version>3.1.3</kcl.version>
-        <netty.version>4.2.15.Final</netty.version>
+        <netty.version>4.2.16.Final</netty.version>
         <netty-reactive.version>2.0.6</netty-reactive.version>
         <fasterxml-jackson.version>2.18.8</fasterxml-jackson.version>
         <logback.version>1.3.16</logback.version>
diff --git a/setup.py b/setup.py
index 4a08373..3520c3b 100644
--- a/setup.py
+++ b/setup.py
@@ -42,7 +42,7 @@
 
 PACKAGE_NAME = "amazon_kclpy"
 JAR_DIRECTORY = os.path.join(PACKAGE_NAME, "jars")
-PACKAGE_VERSION = "3.1.3.post3"
+PACKAGE_VERSION = "3.1.3.post4"
 PYTHON_REQUIREMENTS = [
     "boto3",
     # argparse is part of python3.2+