diff --git a/CMakeLists.txt b/CMakeLists.txt
index b71ad3f..fbb5c8c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@ PROJECT ( example )
 cmake_minimum_required( VERSION 3.16 )
 
 FIND_PACKAGE ( PkgConfig REQUIRED )
-PKG_CHECK_MODULES( GTK REQUIRED gtkmm-4.0)
+PKG_CHECK_MODULES( GTK REQUIRED gtkmm-3.0)
 INCLUDE_DIRECTORIES ( ${GTK_INCLUDE_DIRS} )
 
 
diff --git a/install.sh b/install.sh
index fe5e33b..d5bb961 100644
--- a/install.sh
+++ b/install.sh
@@ -34,6 +34,7 @@ if [ ! -d cairomm ]; then
 	git clone https://github.com/freedesktop/cairomm.git
 fi
 cd cairomm
+cp README.md README
 ./autogen.sh --prefix=/usr
 make -j`nproc --ignore=2`
 sudo make install
diff --git a/main.cpp b/main.cpp
index 13b5c1d..12c36f9 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,16 +1,10 @@
 #include <gtkmm.h>
 
-class GTKExample : public Gtk::Window {
-public:
-  GTKExample();
-};
+using namespace Glib;
+using namespace Gtk;
 
-GTKExample::GTKExample(){
-  set_title("GTK Example");
-  set_default_size(800, 450);
-}
-
-int main(int argc, char ** argv){
-  auto app = Gtk::Application::create("com.example.gtk");
-  return app->make_window_and_run<GTKExample>(argc, argv);
+int main(int argc, char* argv[]) {
+  auto application = Application::create(argc, argv);
+  Window window;
+  return application->run(window);
 }
\ No newline at end of file