diff --git a/inngest-test-server/build.gradle.kts b/inngest-test-server/build.gradle.kts
index 4ad16192..bde91a5f 100644
--- a/inngest-test-server/build.gradle.kts
+++ b/inngest-test-server/build.gradle.kts
@@ -30,7 +30,7 @@ dependencies {
 }
 
 // Apply a specific Java toolchain to ease working on different environments.
-java { toolchain { languageVersion.set(JavaLanguageVersion.of(20)) } }
+java { toolchain { languageVersion.set(JavaLanguageVersion.of(17)) } }
 
 application {
     // Define the main class for the application.