diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c0b1353f..e6a846db 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,8 +20,6 @@ jobs:
     strategy:
       matrix:
         java: 
-          - 11
-          - 17
           - 21
     name: Build and Test
     runs-on: ubuntu-latest
@@ -56,8 +54,6 @@ jobs:
     strategy:
       matrix:
         java: 
-          - 11
-          - 17
           - 21
     name: Build and Test
     runs-on: windows-latest
diff --git a/DEVELOPER_GUIDE.md b/DEVELOPER_GUIDE.md
index d4a44c46..8975ecb6 100644
--- a/DEVELOPER_GUIDE.md
+++ b/DEVELOPER_GUIDE.md
@@ -1,7 +1,7 @@
 - [Developer Guide](#developer-guide)
   - [Forking and Cloning](#forking-and-cloning)
   - [Install Prerequisites](#install-prerequisites)
-    - [JDK 11](#jdk-11)
+    - [JDK 21](#jdk-21)
   - [Building](#building)
   - [Using IntelliJ IDEA](#using-intellij-idea)
   - [Submitting Changes](#submitting-changes)
@@ -16,9 +16,9 @@ Fork this repository on GitHub, and clone locally with `git clone`.
 
 ### Install Prerequisites
 
-#### JDK 11
+#### JDK 21
 
-OpenSearch components build using Java 11 at a minimum. This means you must have a JDK 11 installed with the environment variable `JAVA_HOME` referencing the path to Java home for your JDK 11 installation, e.g. `JAVA_HOME=/usr/lib/jvm/jdk-11`.
+OpenSearch components build using Java 21 at a minimum. This means you must have a JDK 21 installed with the environment variable `JAVA_HOME` referencing the path to Java home for your JDK 21 installation, e.g. `JAVA_HOME=/usr/lib/jvm/jdk-21`.
 
 ### Building
 
diff --git a/build.gradle b/build.gradle
index 4b0df736..332ae8d4 100644
--- a/build.gradle
+++ b/build.gradle
@@ -9,7 +9,7 @@ buildscript {
         opensearch_version = System.getProperty("opensearch.version", "3.0.0-SNAPSHOT")
         isSnapshot = "true" == System.getProperty("build.snapshot", "true")
         buildVersionQualifier = System.getProperty("build.version_qualifier", "")
-        kotlin_version = System.getProperty("kotlin.version", "1.8.21")
+        kotlin_version = System.getProperty("kotlin.version", "1.9.25")
     }
 
     repositories {
@@ -30,7 +30,7 @@ buildscript {
 plugins {
     id 'java-library'
     id 'maven-publish'
-    id 'com.diffplug.spotless' version '6.22.0'
+    id 'com.diffplug.spotless' version '6.25.0'
 }
 
 repositories {
@@ -51,8 +51,8 @@ allprojects {
     }
 }
 
-targetCompatibility = JavaVersion.VERSION_11
-sourceCompatibility = JavaVersion.VERSION_11
+targetCompatibility = JavaVersion.VERSION_21
+sourceCompatibility = JavaVersion.VERSION_21
 
 apply plugin: 'java'
 apply plugin: 'jacoco'
@@ -143,13 +143,13 @@ tasks.register('ktlintFormat', JavaExec) {
 compileKotlin {
     kotlinOptions {
         freeCompilerArgs = ['-Xjsr305=strict']
-        jvmTarget = "11"
+        jvmTarget = "21"
     }
 }
 
 compileTestKotlin {
     kotlinOptions {
-        jvmTarget = "11"
+        jvmTarget = "21"
     }
 }