diff --git a/lib/kotlin/build.gradle.kts b/lib/kotlin/build.gradle.kts
index 0ec8859..cd52e7f 100644
--- a/lib/kotlin/build.gradle.kts
+++ b/lib/kotlin/build.gradle.kts
@@ -36,10 +36,14 @@
 
 kotlin {
     jvmToolchain {
-        (this as JavaToolchainSpec).languageVersion.set(JavaLanguageVersion.of(11))
+        (this as JavaToolchainSpec).languageVersion.set(JavaLanguageVersion.of(8))
     }
 }
 
+tasks.withType<KotlinCompile> {
+    kotlinOptions.jvmTarget = "1.8"
+}
+
 tasks {
     if (JavaVersion.current().isJava11Compatible) {
         ktfmt {