diff --git a/kontor-spring/build.gradle b/kontor-spring/build.gradle
index e49cbac..1e64aa8 100644
--- a/kontor-spring/build.gradle
+++ b/kontor-spring/build.gradle
@@ -44,7 +44,7 @@ repositories {
 }
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_21
+    sourceCompatibility = JavaVersion.VERSION_17
 }
 
 configurations {
diff --git a/kontor-spring/src/main/java/de/thpeetz/kontor/services/ComicService.java b/kontor-spring/src/main/java/de/thpeetz/kontor/services/ComicService.java
index 3f4252e..fcd082e 100644
--- a/kontor-spring/src/main/java/de/thpeetz/kontor/services/ComicService.java
+++ b/kontor-spring/src/main/java/de/thpeetz/kontor/services/ComicService.java
@@ -96,7 +96,9 @@ public class ComicService {
         if (searchFilter == null) return comicRepository.findAll();
         if (searchFilter.getFilterOptions().isEmpty()) return comicRepository.search(searchFilter.getSearchTerm());
         if (searchFilter.getFilterOptions().size() == 1) {
-            FilterOption option = searchFilter.getFilterOptions().getFirst();
+            //TODO use with Java 21
+	    //FilterOption option = searchFilter.getFilterOptions().getFirst();
+            FilterOption option = searchFilter.getFilterOptions().get(0);
             if (searchFilter.getSearchTerm() != null && !searchFilter.getSearchTerm().isEmpty()) {
                 switch (option.getName()) {
                     case "Bestellung":