diff --git a/build.gradle b/build.gradle
index 6ddb752..3537b8d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -5,6 +5,9 @@
     id "com.diffplug.gradle.spotless" version "3.27.0"
 }
 
+sourceCompatibility = 11
+targetCompatibility = 11
+
 sourceSets {
     main {
         scala {
@@ -81,8 +84,5 @@
   }
 }
 
-sourceCompatibility = 13
-targetCompatibility = 13
-
 group 'eu.mulk'
 version '0.1.0-SNAPSHOT'