diff --git a/build.gradle b/build.gradle
index 9becc03..294fcbf 100644
--- a/build.gradle
+++ b/build.gradle
@@ -13,7 +13,7 @@ group = 'nu.studer'
 version = '3.0.5-DEV'
 
 dependencies {
-    testImplementation 'org.spockframework:spock-core:2.3-groovy-4.0'
+    testImplementation 'org.spockframework:spock-core:2.3-groovy-3.0'
 }
 
 tasks.withType(AbstractCompile).configureEach {