diff --git a/CursorLang/Models/AppSettings.cs b/CursorLang/Models/AppSettings.cs
index 03a1031..a06ab92 100644
--- a/CursorLang/Models/AppSettings.cs
+++ b/CursorLang/Models/AppSettings.cs
@@ -19,12 +19,14 @@ public sealed partial class AppSettings : ObservableObject
     [ObservableProperty]
     private AppTheme _theme = AppTheme.System;
 
+    /// <summary>Where the popup is shown: at the cursor, at the caret or at a fixed point.</summary>
     [ObservableProperty]
     private PopupPlacementMode _placementMode = PopupPlacementMode.AtCursor;
 
     // The side and the offset are stored per mode: the cursor and the caret call for
     // different settings, and switching the mode does not reset them
 
+    /// <summary>The side of the cursor the popup is put on.</summary>
     [ObservableProperty]
     private AnchorSide _cursorSide = AnchorSide.BottomRight;
 
@@ -32,6 +34,7 @@ public sealed partial class AppSettings : ObservableObject
     [ObservableProperty]
     private double _cursorOffset = 16;
 
+    /// <summary>The side of the caret the popup is put on.</summary>
     [ObservableProperty]
     private AnchorSide _caretSide = AnchorSide.BottomRight;
 
@@ -39,6 +42,9 @@ public sealed partial class AppSettings : ObservableObject
     [ObservableProperty]
     private double _caretOffset = 16;
 
+    /// <summary>
+    /// The place on the monitor for the <see cref="PopupPlacementMode.FixedPoint"/> mode.
+    /// </summary>
     [ObservableProperty]
     private ScreenPosition _screenPosition = ScreenPosition.BottomRight;
 
@@ -46,6 +52,7 @@ public sealed partial class AppSettings : ObservableObject
     [ObservableProperty]
     private double _screenMargin = 24;
 
+    /// <summary>The size of the layout name in the popup, in WPF units.</summary>
     [ObservableProperty]
     private double _fontSize = 20;
 
@@ -71,15 +78,33 @@ public sealed partial class AppSettings : ObservableObject
     [ObservableProperty]
     private double _capsLockHoldMilliseconds = 300;
 
+    /// <summary>
+    /// Ask the repository about new versions on startup. A check can always be
+    /// started by hand — this setting turns off only the automatic one.
+    /// </summary>
+    [ObservableProperty]
+    private bool _checkForUpdates = true;
+
+    /// <summary>
+    /// When the application last asked about new versions successfully.
+    /// Stored so as not to go to the network on every startup.
+    /// </summary>
+    [ObservableProperty]
+    private DateTimeOffset? _lastUpdateCheck;
+
+    /// <summary>The fill of the popup. The opacity is set by <see cref="Opacity"/>.</summary>
     [ObservableProperty]
     private Color _backgroundColor = Color.FromRgb(0x20, 0x20, 0x20);
 
+    /// <summary>The colour of the layout name in the popup.</summary>
     [ObservableProperty]
     private Color _foregroundColor = Color.FromRgb(0xFF, 0xFF, 0xFF);
 
+    /// <summary><see cref="DurationMilliseconds"/> as a <see cref="TimeSpan"/>.</summary>
     [JsonIgnore]
     public TimeSpan Duration => TimeSpan.FromMilliseconds(DurationMilliseconds);
 
+    /// <summary><see cref="CapsLockHoldMilliseconds"/> as a <see cref="TimeSpan"/>.</summary>
     [JsonIgnore]
     public TimeSpan CapsLockHoldDelay => TimeSpan.FromMilliseconds(CapsLockHoldMilliseconds);
 }
diff --git a/CursorLang/Models/ReleaseInfo.cs b/CursorLang/Models/ReleaseInfo.cs
new file mode 100644
index 0000000..7249519
--- /dev/null
+++ b/CursorLang/Models/ReleaseInfo.cs
@@ -0,0 +1,18 @@
+namespace CursorLang.Models;
+
+/// <summary>
+/// A file attached to a release.
+/// </summary>
+/// <param name="FileName">The name the file is saved to disk under.</param>
+/// <param name="Url">A direct link to the content.</param>
+/// <param name="Size">The size in bytes; zero when the hosting did not report it.</param>
+public sealed record ReleaseAsset(string FileName, Uri Url, long Size);
+
+/// <summary>
+/// A release found in the repository.
+/// </summary>
+/// <param name="Version">The version parsed from the tag.</param>
+/// <param name="Tag">The tag as is — that is what the interface shows.</param>
+/// <param name="PageUrl">The release page: the release notes live there too.</param>
+/// <param name="Package">The MSIX package the application updates itself with.</param>
+public sealed record ReleaseInfo(Version Version, string Tag, Uri? PageUrl, ReleaseAsset Package);
diff --git a/CursorLang/Models/StartupState.cs b/CursorLang/Models/StartupState.cs
new file mode 100644
index 0000000..d25641a
--- /dev/null
+++ b/CursorLang/Models/StartupState.cs
@@ -0,0 +1,30 @@
+namespace CursorLang.Models;
+
+/// <summary>
+/// The state of startup. Follows <c>StartupTaskState</c> of Windows: the user and
+/// the administrator each have their own way of forbidding startup, and the app has
+/// to tell them apart so as not to promise what it cannot do.
+/// </summary>
+public enum StartupState
+{
+    /// <summary>Windows will not answer about startup — the setting is not shown.</summary>
+    Unavailable,
+
+    /// <summary>Off, and the app can switch it on.</summary>
+    Disabled,
+
+    /// <summary>On.</summary>
+    Enabled,
+
+    /// <summary>
+    /// Switched off by the user in the settings of Windows. It goes back on only
+    /// there: a ban by the user is not for the app to overrule.
+    /// </summary>
+    DisabledByUser,
+
+    /// <summary>Forbidden by the policy of the organisation.</summary>
+    DisabledByPolicy,
+
+    /// <summary>Switched on by the policy of the organisation and not to be switched off.</summary>
+    EnabledByPolicy,
+}
diff --git a/CursorLang/Models/UpdateStatus.cs b/CursorLang/Models/UpdateStatus.cs
new file mode 100644
index 0000000..5d59e8d
--- /dev/null
+++ b/CursorLang/Models/UpdateStatus.cs
@@ -0,0 +1,29 @@
+namespace CursorLang.Models;
+
+/// <summary>
+/// Which step the update is at. One value — one state of the interface:
+/// the caption, the button and the progress bar are shown from it.
+/// </summary>
+public enum UpdateStatus
+{
+    /// <summary>There have been no checks yet.</summary>
+    Idle,
+
+    /// <summary>A request to the repository is in flight.</summary>
+    Checking,
+
+    /// <summary>The latest version is installed.</summary>
+    UpToDate,
+
+    /// <summary>There is a newer version — it can be downloaded.</summary>
+    Available,
+
+    /// <summary>The package is downloading.</summary>
+    Downloading,
+
+    /// <summary>The package is downloaded and ready to install.</summary>
+    Ready,
+
+    /// <summary>The check or the download failed.</summary>
+    Failed,
+}