diff --git a/hamming-error-correction/pom.xml b/hamming-error-correction/pom.xml
index a0f1a97..797e140 100644
--- a/hamming-error-correction/pom.xml
+++ b/hamming-error-correction/pom.xml
@@ -295,7 +295,7 @@
     </build>
 
     <properties>
-        <kotlin.version>1.9.10</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
         <junit.version>5.8.2</junit.version>
         <jmh.version>1.35</jmh.version>
         <jmh.generator>default</jmh.generator>
diff --git a/kotlin-collections/pom.xml b/kotlin-collections/pom.xml
index a148118..6595a5b 100644
--- a/kotlin-collections/pom.xml
+++ b/kotlin-collections/pom.xml
@@ -8,7 +8,7 @@
     <version>1.0</version>
 
     <properties>
-        <kotlin.version>1.9.10</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
         <junit.version>5.8.2</junit.version>
         <mockito.version>2.8.0</mockito.version>
     </properties>
diff --git a/kotlin-null-nonsafety/pom.xml b/kotlin-null-nonsafety/pom.xml
index 20dea00..b185e35 100644
--- a/kotlin-null-nonsafety/pom.xml
+++ b/kotlin-null-nonsafety/pom.xml
@@ -8,7 +8,7 @@
     <version>1.0</version>
 
     <properties>
-        <kotlin.version>1.9.10</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
     </properties>
 
     <dependencies>
diff --git a/kotlin-type-inference/pom.xml b/kotlin-type-inference/pom.xml
index c36d310..d5b867d 100644
--- a/kotlin-type-inference/pom.xml
+++ b/kotlin-type-inference/pom.xml
@@ -8,7 +8,7 @@
     <version>1.0</version>
 
     <properties>
-        <kotlin.version>1.9.10</kotlin.version>
+        <kotlin.version>1.9.21</kotlin.version>
         <junit.version>5.8.2</junit.version>
         <mockito.version>2.8.0</mockito.version>
     </properties>