diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 1733fa1..17e509b 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -28,13 +28,13 @@ dependencies {
 // Apply a specific Java toolchain to ease working on different environments.
 java {
     toolchain {
-        languageVersion.set(JavaLanguageVersion.of(17))
+        languageVersion.set(JavaLanguageVersion.of(21))
     }
 }
 
 application {
     // Define the main class for the application.
-    mainClass.set("gui.XL")
+    mainClass.set("xl.App")
 }
 
 tasks.named<Test>("test") {
diff --git a/makefile b/makefile
index b3ce6d2..2e45223 100644
--- a/makefile
+++ b/makefile
@@ -3,6 +3,7 @@ GITHASH := $(shell git rev-parse --short HEAD)$(shell git diff-index --quiet HEA
 TARNAME := xl-imbus-$(GITHASH).tar.gz
 
 run:
+	echo $(GITHASH)
 	./gradlew run
 
 watch: