Add very simple in-game update checker/display.

osu.Desktop/OsuGameDesktop.cs

@@ -11,6 +11,7 @@
 using osu.Framework.Platform;
 using osu.Framework.Desktop.Platform;
 using osu.Game.Database;
+using osu.Desktop.Overlays;
 
 namespace osu.Desktop
 {
@@ -22,6 +23,13 @@ public OsuGameDesktop(string[] args = null)
 
         }
 
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            (new VersionManager()).Preload(this, Add);
+        }
+
         public override void SetHost(BasicGameHost host)
         {
             base.SetHost(host);

osu.Desktop/Overlays/VersionManager.cs

@@ -0,0 +1,93 @@
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Overlays;
+using osu.Game.Overlays.Notifications;
+using Squirrel;
+using System.Reflection;
+
+namespace osu.Desktop.Overlays
+{
+    public class VersionManager : OverlayContainer
+    {
+        private UpdateManager updateManager;
+        private NotificationManager notification;
+
+        [BackgroundDependencyLoader]
+        private void load(NotificationManager notification)
+        {
+            this.notification = notification;
+
+            AutoSizeAxes = Axes.Both;
+            Anchor = Anchor.BottomCentre;
+            Origin = Anchor.BottomCentre;
+
+            var asm = Assembly.GetEntryAssembly().GetName();
+            Add(new OsuSpriteText
+            {
+                Text = $@"osu!lazer v{asm.Version}"
+            });
+
+            updateChecker();
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            State = Visibility.Visible;
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            updateManager?.Dispose();
+        }
+
+        private async void updateChecker()
+        {
+            updateManager = await UpdateManager.GitHubUpdateManager(@"https://github.com/ppy/osu", @"osulazer", null, null, true);
+            var info = await updateManager.CheckForUpdate();
+            if (info.ReleasesToApply.Count > 0)
+            {
+                ProgressNotification n = new UpdateProgressNotification
+                {
+                    Text = @"Downloading update..."
+                };
+                Schedule(() => notification.Post(n));
+                Schedule(() => n.State = ProgressNotificationState.Active);
+                await updateManager.DownloadReleases(info.ReleasesToApply, (int p) => Schedule(() => n.Progress = p / 100f));
+                Schedule(() => n.Text = @"Installing update...");
+                await updateManager.ApplyReleases(info, (int p) => Schedule(() => n.Progress = p / 100f));
+                Schedule(() => n.State = ProgressNotificationState.Completed);
+
+            }
+            else
+            {
+                //check again every 30 minutes.
+                Scheduler.AddDelayed(updateChecker, 60000 * 30);
+            }
+        }
+
+        protected override void PopIn()
+        {
+        }
+
+        protected override void PopOut()
+        {
+        }
+
+        class UpdateProgressNotification : ProgressNotification
+        {
+            protected override Notification CreateCompletionNotification() => new ProgressCompletionNotification(this)
+            {
+                Text = @"Update ready to install. Click to restart!",
+                Activated = () =>
+                {
+                    UpdateManager.RestartApp();
+                    return true;
+                }
+            };
+        }
+    }
+}