diff --git a/build.gradle.kts b/build.gradle.kts
index 102463ca..d6f34fee 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -9,7 +9,7 @@ val mockWebServerVersion = "4.12.0"
 val jacksonVersion = "2.16.0"
 val nettyVersion = "4.1.101.Final"
 val junitJupiterVersion = "5.10.1"
-val kotlinVersion = "1.9.20"
+val kotlinVersion = "1.9.21"
 val freemarkerVersion = "2.3.32"
 val kotestVersion = "5.8.0"
 val bouncyCastleVersion = "1.70"