diff --git a/mqtt-cli-plugins/build.gradle.kts b/mqtt-cli-plugins/build.gradle.kts
index 05ff2c2c2..94e92779c 100644
--- a/mqtt-cli-plugins/build.gradle.kts
+++ b/mqtt-cli-plugins/build.gradle.kts
@@ -6,7 +6,7 @@ group = "com.hivemq"
 
 java {
     toolchain {
-        languageVersion.set(JavaLanguageVersion.of(8))
+        languageVersion = JavaLanguageVersion.of(8)
     }
 }