diff --git a/wrappers/kotlin/lib/build.gradle.kts b/wrappers/kotlin/lib/build.gradle.kts
index e98c00fc..fef23569 100644
--- a/wrappers/kotlin/lib/build.gradle.kts
+++ b/wrappers/kotlin/lib/build.gradle.kts
@@ -41,7 +41,7 @@ dependencies {
 // Apply a specific Java toolchain to ease working on different environments.
 java {
     toolchain {
-        languageVersion = JavaLanguageVersion.of(21)
+        languageVersion = JavaLanguageVersion.of(17)
     }
 }