diff --git a/.github/workflows/bld.yml b/.github/workflows/bld.yml
index be80a2f..1fed067 100644
--- a/.github/workflows/bld.yml
+++ b/.github/workflows/bld.yml
@@ -15,8 +15,8 @@ jobs:
 
     strategy:
       matrix:
-        java-version: [17, 21, 24]
-        kotlin-version: [1.9.25, 2.1.20]
+        java-version: [ 17, 21, 24 ]
+        kotlin-version: [ 1.9.25, 2.1.21 ]
 
     steps:
       - name: Checkout source repository
diff --git a/.idea/kotlinc.xml b/.idea/kotlinc.xml
index 3e29a08..6f5e579 100644
--- a/.idea/kotlinc.xml
+++ b/.idea/kotlinc.xml
@@ -16,6 +16,6 @@
     </option>
   </component>
   <component name="KotlinJpsPluginSettings">
-    <option name="version" value="2.0.0" />
+    <option name="version" value="2.1.21" />
   </component>
-</project>
\ No newline at end of file
+</project>
diff --git a/README.md b/README.md
index 441e433..81404ec 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 [![License (3-Clause BSD)](https://img.shields.io/badge/license-BSD%203--Clause-blue.svg?style=flat-square)](https://opensource.org/licenses/BSD-3-Clause)
-[![Kotlin](https://img.shields.io/badge/kotlin-2.1.20-7f52ff)](https://kotlinlang.org/)
+[![Kotlin](https://img.shields.io/badge/kotlin-2.1.21-7f52ff)](https://kotlinlang.org/)
 [![bld](https://img.shields.io/badge/2.2.1-FA9052?label=bld&labelColor=2392FF)](https://rife2.com/bld)
 [![Release](https://img.shields.io/github/release/ethauvin/akismet-kotlin.svg)](https://github.com/ethauvin/akismet-kotlin/releases/latest)
 [![Nexus Snapshot](https://img.shields.io/nexus/s/net.thauvin.erik/akismet-kotlin?label=snapshot&server=https%3A%2F%2Foss.sonatype.org%2F)](https://oss.sonatype.org/content/repositories/snapshots/net/thauvin/erik/akismet-kotlin/)
diff --git a/examples/bld/lib/bld/bld-wrapper.properties b/examples/bld/lib/bld/bld-wrapper.properties
index 1ffe3ff..1f1009d 100644
--- a/examples/bld/lib/bld/bld-wrapper.properties
+++ b/examples/bld/lib/bld/bld-wrapper.properties
@@ -1,7 +1,7 @@
 bld.downloadExtensionJavadoc=false
 bld.downloadExtensionSources=true
 bld.downloadLocation=
-bld.extension-kotlin=com.uwyn.rife2:bld-kotlin:1.0.4
+bld.extension-kotlin=com.uwyn.rife2:bld-kotlin:1.1.0-SNAPSHOT
 bld.repositories=MAVEN_LOCAL,MAVEN_CENTRAL,RIFE2_SNAPSHOTS,RIFE2_RELEASES
 bld.sourceDirectories=
 bld.version=2.2.1
diff --git a/examples/gradle/.idea/kotlinc.xml b/examples/gradle/.idea/kotlinc.xml
index 131e44d..750533e 100644
--- a/examples/gradle/.idea/kotlinc.xml
+++ b/examples/gradle/.idea/kotlinc.xml
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
   <component name="KotlinJpsPluginSettings">
-    <option name="version" value="2.1.20" />
+    <option name="version" value="2.1.21" />
   </component>
-</project>
\ No newline at end of file
+</project>
diff --git a/examples/gradle/build.gradle.kts b/examples/gradle/build.gradle.kts
index 1d9e3ef..ce2a126 100644
--- a/examples/gradle/build.gradle.kts
+++ b/examples/gradle/build.gradle.kts
@@ -1,7 +1,7 @@
 plugins {
     id("application")
     id("com.github.ben-manes.versions") version "0.51.0"
-    kotlin("jvm") version "2.1.20"
+    kotlin("jvm") version "2.1.21"
 }
 
 defaultTasks(ApplicationPlugin.TASK_RUN_NAME)
diff --git a/pom.xml b/pom.xml
index 33a7c4f..2592b1f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -18,19 +18,19 @@
     <dependency>
       <groupId>org.jetbrains.kotlin</groupId>
       <artifactId>kotlin-stdlib</artifactId>
-      <version>2.1.20</version>
+      <version>2.1.21</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
       <groupId>org.jetbrains.kotlin</groupId>
       <artifactId>kotlin-stdlib-jdk7</artifactId>
-      <version>2.1.20</version>
+      <version>2.1.21</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
       <groupId>org.jetbrains.kotlin</groupId>
       <artifactId>kotlin-stdlib-jdk8</artifactId>
-      <version>2.1.20</version>
+      <version>2.1.21</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
@@ -48,7 +48,7 @@
     <dependency>
       <groupId>org.jetbrains.kotlinx</groupId>
       <artifactId>kotlinx-serialization-json</artifactId>
-      <version>1.8.0</version>
+      <version>1.8.1</version>
       <scope>compile</scope>
     </dependency>
     <dependency>
diff --git a/src/bld/java/net/thauvin/erik/AkismetBuild.java b/src/bld/java/net/thauvin/erik/AkismetBuild.java
index 8ac1a3d..7bb422b 100644
--- a/src/bld/java/net/thauvin/erik/AkismetBuild.java
+++ b/src/bld/java/net/thauvin/erik/AkismetBuild.java
@@ -71,7 +71,7 @@ public class AkismetBuild extends Project {
         repositories = List.of(MAVEN_LOCAL, MAVEN_CENTRAL);
 
         var okHttp = version(4, 12, 0);
-        final var kotlin = version(2, 1, 20);
+        final var kotlin = version(2, 1, 21);
         scope(compile)
                 .include(dependency("org.jetbrains.kotlin", "kotlin-stdlib", kotlin))
                 .include(dependency("org.jetbrains.kotlin", "kotlin-stdlib-jdk7", kotlin))
@@ -141,7 +141,7 @@ public class AkismetBuild extends Project {
         var op = new CompileKotlinOperation()
                 .fromProject(this)
                 .plugins(CompilerPlugin.KOTLIN_SERIALIZATION);
-        op.compileOptions().verbose(true);
+        op.compileOptions().languageVersion("1.9").verbose(true);
         op.execute();
     }