diff --git a/tutorials/kotlin/Polygons/build.gradle b/tutorials/kotlin/Polygons/build.gradle
index 9c260094..3fe1d963 100644
--- a/tutorials/kotlin/Polygons/build.gradle
+++ b/tutorials/kotlin/Polygons/build.gradle
@@ -1,7 +1,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 
 buildscript {
-    ext.kotlin_version = '1.4.20'
+    ext.kotlin_version = '1.4.21'
     repositories {
         jcenter()
         google()