diff --git a/src/main/java/io/github/gaming32/worldhost/WorldHost.java b/src/main/java/io/github/gaming32/worldhost/WorldHost.java
index fe9d820..d60cdd8 100644
--- a/src/main/java/io/github/gaming32/worldhost/WorldHost.java
+++ b/src/main/java/io/github/gaming32/worldhost/WorldHost.java
@@ -873,8 +873,13 @@ private static Path getGameDir() {
     //$$ @Mod.EventBusSubscriber(modid = MOD_ID, bus = Mod.EventBusSubscriber.Bus.MOD, value = Dist.CLIENT)
     //#endif
     //$$ public static class ClientModEvents {
+    //$$     // Forge 47.1.3 can call FMLClientSetupEvent twice.
+    //$$     private static boolean initialized = false;
+    //$$
     //$$     @SubscribeEvent
-    //$$     public static void onClientSetup(FMLClientSetupEvent event) {
+    //$$     public static synchronized void onClientSetup(FMLClientSetupEvent event) {
+    //$$         if (initialized) return;
+    //$$         initialized = true;
     //$$         init();
     //$$         final BiFunction<Minecraft, Screen, Screen> screenFunction =
     //$$             (mc, screen) -> new WorldHostConfigScreen(screen);
diff --git a/version.gradle.kts b/version.gradle.kts
index e3f87b5..d3c373f 100644
--- a/version.gradle.kts
+++ b/version.gradle.kts
@@ -139,6 +139,12 @@ unimined.minecraft {
         remap(tasks.shadeDowngradedApi.get(), "remapJar")
         tasks.assemble.get().dependsOn("remapJar")
     }
+
+    runs {
+        config("client") {
+            javaVersion = JavaVersion.VERSION_21
+        }
+    }
 }
 val minecraft = unimined.minecrafts[sourceSets.main.get()]