diff --git a/fints4k-jvm/build.gradle b/fints4k-jvm/build.gradle
index 23bfc960..377323fc 100644
--- a/fints4k-jvm/build.gradle
+++ b/fints4k-jvm/build.gradle
@@ -1,8 +1,8 @@
 apply plugin: 'java-library'
 apply plugin: 'kotlin'
 
-sourceCompatibility = "8"
-targetCompatibility = "8"
+sourceCompatibility = "1.7"
+targetCompatibility = "1.7"
 
 
 dependencies {