diff --git a/Cargo.lock b/Cargo.lock
index 0709606..ffdf99c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4,33 +4,9 @@ version = 3
 
 [[package]]
 name = "anyhow"
-version = "1.0.47"
+version = "1.0.49"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38d9ff5d688f1c13395289f67db01d4826b46dd694e7580accdc3e8430f2d98e"
-
-[[package]]
-name = "atk"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a83b21d2aa75e464db56225e1bda2dd5993311ba1095acaa8fa03d1ae67026ba"
-dependencies = [
- "atk-sys",
- "bitflags",
- "glib",
- "libc",
-]
-
-[[package]]
-name = "atk-sys"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "badcf670157c84bb8b1cf6b5f70b650fed78da2033c9eed84c4e49b11cbe83ea"
-dependencies = [
- "glib-sys",
- "gobject-sys",
- "libc",
- "system-deps",
-]
+checksum = "0a03e93e97a28fbc9f42fbc5ba0886a3c67eb637b476dbee711f80a6ffe8223d"
 
 [[package]]
 name = "autocfg"
@@ -65,7 +41,7 @@ checksum = "b448b876970834fda82ba3aeaccadbd760206b75388fc5c1b02f1e343b697570"
 dependencies = [
  "glib-sys",
  "libc",
- "system-deps",
+ "system-deps 3.2.0",
 ]
 
 [[package]]
@@ -77,6 +53,15 @@ dependencies = [
  "smallvec",
 ]
 
+[[package]]
+name = "cfg-expr"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "edae0b9625d1fce32f7d64b71784d9b1bf8469ec1a9c417e44aaf16a9cbd7571"
+dependencies = [
+ "smallvec",
+]
+
 [[package]]
 name = "either"
 version = "1.6.1"
@@ -95,24 +80,24 @@ dependencies = [
 
 [[package]]
 name = "futures-channel"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5da6ba8c3bb3c165d3c7319fc1cc8304facf1fb8db99c5de877183c08a273888"
+checksum = "7fc8cd39e3dbf865f7340dce6a2d401d24fd37c6fe6c4f0ee0de8bfca2252d27"
 dependencies = [
  "futures-core",
 ]
 
 [[package]]
 name = "futures-core"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88d1c26957f23603395cd326b0ffe64124b818f4449552f960d815cfba83a53d"
+checksum = "629316e42fe7c2a0b9a65b47d159ceaa5453ab14e8f0a3c5eedbb8cd55b4a445"
 
 [[package]]
 name = "futures-executor"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "45025be030969d763025784f7f355043dc6bc74093e4ecc5000ca4dc50d8745c"
+checksum = "7b808bf53348a36cab739d7e04755909b9fcaaa69b7d7e588b37b6ec62704c97"
 dependencies = [
  "futures-core",
  "futures-task",
@@ -121,23 +106,22 @@ dependencies = [
 
 [[package]]
 name = "futures-io"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "522de2a0fe3e380f1bc577ba0474108faf3f6b18321dbf60b3b9c39a75073377"
+checksum = "e481354db6b5c353246ccf6a728b0c5511d752c08da7260546fc0933869daa11"
 
 [[package]]
 name = "futures-task"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d3d00f4eddb73e498a54394f228cd55853bdf059259e8e7bc6e69d408892e99"
+checksum = "dabf1872aaab32c886832f2276d2f5399887e2bd613698a02359e4ea83f8de12"
 
 [[package]]
 name = "futures-util"
-version = "0.3.17"
+version = "0.3.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "36568465210a3a6ee45e1f165136d68671471a501e632e9a98d96872222b5481"
+checksum = "41d22213122356472061ac0f1ab2cee28d2bac8491410fd68c2af53d1cedb83e"
 dependencies = [
- "autocfg",
  "futures-core",
  "futures-task",
  "pin-project-lite",
@@ -145,22 +129,6 @@ dependencies = [
  "slab",
 ]
 
-[[package]]
-name = "gdk"
-version = "0.14.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b9d749dcfc00d8de0d7c3a289e04a04293eb5ba3d8a4e64d64911d481fa9933b"
-dependencies = [
- "bitflags",
- "cairo-rs",
- "gdk-pixbuf",
- "gdk-sys",
- "gio",
- "glib",
- "libc",
- "pango",
-]
-
 [[package]]
 name = "gdk-pixbuf"
 version = "0.14.0"
@@ -183,24 +151,40 @@ dependencies = [
  "glib-sys",
  "gobject-sys",
  "libc",
- "system-deps",
+ "system-deps 3.2.0",
 ]
 
 [[package]]
-name = "gdk-sys"
-version = "0.14.0"
+name = "gdk4"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e091b3d3d6696949ac3b3fb3c62090e5bfd7bd6850bef5c3c5ea701de1b1f1e"
+checksum = "f97a162c17214d1bf981af3f683156a0b1667dd1927057c4f0a68513251ecf0f"
+dependencies = [
+ "bitflags",
+ "cairo-rs",
+ "gdk-pixbuf",
+ "gdk4-sys",
+ "gio",
+ "glib",
+ "libc",
+ "pango",
+]
+
+[[package]]
+name = "gdk4-sys"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9498f4e06969fb96a4e4234dfe1d308a3ac6b120b3c6d93e3ec5c77fe88bc6d5"
 dependencies = [
  "cairo-sys-rs",
  "gdk-pixbuf-sys",
  "gio-sys",
  "glib-sys",
  "gobject-sys",
+ "graphene-sys",
  "libc",
  "pango-sys",
- "pkg-config",
- "system-deps",
+ "system-deps 5.0.0",
 ]
 
 [[package]]
@@ -229,7 +213,7 @@ dependencies = [
  "glib-sys",
  "gobject-sys",
  "libc",
- "system-deps",
+ "system-deps 3.2.0",
  "winapi",
 ]
 
@@ -274,7 +258,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1c1d60554a212445e2a858e42a0e48cece1bd57b311a19a9468f70376cf554ae"
 dependencies = [
  "libc",
- "system-deps",
+ "system-deps 3.2.0",
 ]
 
 [[package]]
@@ -285,58 +269,96 @@ checksum = "aa92cae29759dae34ab5921d73fff5ad54b3d794ab842c117e36cafc7994c3f5"
 dependencies = [
  "glib-sys",
  "libc",
- "system-deps",
+ "system-deps 3.2.0",
 ]
 
 [[package]]
-name = "gtk"
-version = "0.14.3"
+name = "graphene-rs"
+version = "0.14.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2eb51122dd3317e9327ec1e4faa151d1fa0d95664cd8fb8dcfacf4d4d29ac70c"
+checksum = "e3380f132530ef9eb9e0a2bac180e30390aa5e49892d20294f822a974117a563"
+dependencies = [
+ "glib",
+ "graphene-sys",
+ "libc",
+]
+
+[[package]]
+name = "graphene-sys"
+version = "0.14.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9a9ac7450b3aa80792513a3c029920a2ede419de13fb5169a4e51b07a5685332"
+dependencies = [
+ "glib-sys",
+ "libc",
+ "pkg-config",
+ "system-deps 3.2.0",
+]
+
+[[package]]
+name = "gsk4"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eff59ca46c4fc5087fd7a0c3770a71ea4b6e94f8c24c12e2c2e8538f9f6fd764"
+dependencies = [
+ "bitflags",
+ "cairo-rs",
+ "gdk4",
+ "glib",
+ "graphene-rs",
+ "gsk4-sys",
+ "libc",
+ "pango",
+]
+
+[[package]]
+name = "gsk4-sys"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "13aa53ce70234da02f9954339d988d5ab853d746a8f47a4ae17735ff873545b5"
+dependencies = [
+ "cairo-sys-rs",
+ "gdk4-sys",
+ "glib-sys",
+ "gobject-sys",
+ "graphene-sys",
+ "libc",
+ "pango-sys",
+ "system-deps 5.0.0",
+]
+
+[[package]]
+name = "gtk4"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "58a04f421d1485ba4739e723199f5828bca05ab4e622ed39a96a342b6b1a6a3d"
 dependencies = [
- "atk",
  "bitflags",
  "cairo-rs",
  "field-offset",
  "futures-channel",
- "gdk",
  "gdk-pixbuf",
+ "gdk4",
  "gio",
  "glib",
- "gtk-sys",
- "gtk3-macros",
+ "graphene-rs",
+ "gsk4",
+ "gtk4-macros",
+ "gtk4-sys",
  "libc",
  "once_cell",
  "pango",
- "pkg-config",
 ]
 
 [[package]]
-name = "gtk-sys"
-version = "0.14.0"
+name = "gtk4-macros"
+version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8c14c8d3da0545785a7c5a120345b3abb534010fb8ae0f2ef3f47c027fba303e"
-dependencies = [
- "atk-sys",
- "cairo-sys-rs",
- "gdk-pixbuf-sys",
- "gdk-sys",
- "gio-sys",
- "glib-sys",
- "gobject-sys",
- "libc",
- "pango-sys",
- "system-deps",
-]
-
-[[package]]
-name = "gtk3-macros"
-version = "0.14.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "21de1da96dc117443fb03c2e270b2d34b7de98d0a79a19bbb689476173745b79"
+checksum = "5068d4354af02454f44687adc613100aa98ae11e273cdcac84f89dc08be2b4a1"
 dependencies = [
  "anyhow",
  "heck",
+ "itertools",
  "proc-macro-crate",
  "proc-macro-error",
  "proc-macro2",
@@ -344,6 +366,25 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "gtk4-sys"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e20a64c8f0ddcff8902ff04c130747f2fb7834a43530f75d03d6c71335733b49"
+dependencies = [
+ "cairo-sys-rs",
+ "gdk-pixbuf-sys",
+ "gdk4-sys",
+ "gio-sys",
+ "glib-sys",
+ "gobject-sys",
+ "graphene-sys",
+ "gsk4-sys",
+ "libc",
+ "pango-sys",
+ "system-deps 5.0.0",
+]
+
 [[package]]
 name = "heck"
 version = "0.3.3"
@@ -364,9 +405,9 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.107"
+version = "0.2.108"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fbe5e23404da5b4f555ef85ebed98fb4083e55a00c317800bc2a50ede9f3d219"
+checksum = "8521a1b57e76b1ec69af7599e75e38e7b7fad6610f037db8c79b127201b5d119"
 
 [[package]]
 name = "memoffset"
@@ -405,7 +446,7 @@ dependencies = [
  "glib-sys",
  "gobject-sys",
  "libc",
- "system-deps",
+ "system-deps 3.2.0",
 ]
 
 [[package]]
@@ -439,7 +480,7 @@ checksum = "12295df4f294471248581bc09bef3c38a5e46f1e36d6a37353621a0c6c357e1f"
 name = "polytree-settings"
 version = "0.0.0"
 dependencies = [
- "gtk",
+ "gtk4",
 ]
 
 [[package]]
@@ -559,9 +600,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.81"
+version = "1.0.82"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2afee18b8beb5a596ecb4a2dce128c719b4ba399d34126b9e4396e3f9860966"
+checksum = "8daf5dd0bb60cbd4137b1b587d2fc0ae729bc07cf01cd70b36a1ed5ade3b9d59"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -575,7 +616,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "480c269f870722b3b08d2f13053ce0c2ab722839f472863c3e2d61ff3a1c2fa6"
 dependencies = [
  "anyhow",
- "cfg-expr",
+ "cfg-expr 0.8.1",
  "heck",
  "itertools",
  "pkg-config",
@@ -586,6 +627,19 @@ dependencies = [
  "version-compare",
 ]
 
+[[package]]
+name = "system-deps"
+version = "5.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "18db855554db7bd0e73e06cf7ba3df39f97812cb11d3f75e71c39bf45171797e"
+dependencies = [
+ "cfg-expr 0.9.0",
+ "heck",
+ "pkg-config",
+ "toml",
+ "version-compare",
+]
+
 [[package]]
 name = "thiserror"
 version = "1.0.30"
diff --git a/Cargo.toml b/Cargo.toml
index 4c0d4b6..2f92aee 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,4 +13,4 @@ categories = ["gui"]
 publish = true
 
 [dependencies]
-gtk = "0.14.3"
+gtk = { package = "gtk4", version = "0.3.1" }
diff --git a/src/main.rs b/src/main.rs
index 66f89f0..aac12f7 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,16 +12,10 @@ fn main() {
 }
 
 fn build_ui(app: &Application) {
-    let window = ApplicationWindow::new(app);
+    let window = ApplicationWindow::builder()
+        .application(app)
+        .title("Hello, World!")
+        .build();
 
-    window.set_title("Polytree settings");
-    window.set_border_width(10);
-    window.set_position(WindowPosition::Center);
-    window.set_default_size(350, 70);
-
-    let button = Button::with_label("Press me!");
-
-    window.add(&button);
-
-    window.show_all();
+    window.present();
 }