diff --git a/sdks/kotlin/build.gradle.kts b/sdks/kotlin/build.gradle.kts
index eb50fd1..500986d 100644
--- a/sdks/kotlin/build.gradle.kts
+++ b/sdks/kotlin/build.gradle.kts
@@ -20,7 +20,7 @@ plugins {
 }
 
 kotlin {
-  jvmToolchain(21)
+  jvmToolchain(17)
 }
 
 group = "com.google.testserver"