diff --git a/NET10/BlazorInteractiveServer/Components/Demo/ComplexComponentsDemo.razor b/NET10/BlazorInteractiveServer/Components/Demo/ComplexComponentsDemo.razor
index bf45f91..b74ef99 100644
--- a/NET10/BlazorInteractiveServer/Components/Demo/ComplexComponentsDemo.razor
+++ b/NET10/BlazorInteractiveServer/Components/Demo/ComplexComponentsDemo.razor
@@ -333,7 +333,7 @@
                 </div>
                 <Pagination CurrentPage="CurrentPage" 
                            TotalPages="TotalPages" 
-                           OnPageChange="HandlePageChange" />
+                           CurrentPageChanged="HandlePageChange" />
             </div>
         </div>
     </div>
diff --git a/README.md b/README.md
index 4315130..755dfbf 100644
--- a/README.md
+++ b/README.md
@@ -35,7 +35,7 @@ ShellUI is pre-1.0, so APIs and generated output can still change between minor
 
 ## Capabilities
 
-- The CLI commands are `init`, `add`, `list`, `remove`, `update` and `doctor`, plus `theme init`, `theme apply`, and `theme update`.
+- The CLI commands are `init`, `add`, `list`, `remove`, `update`, `doctor` and `migrate`, plus `theme init`, `theme apply`, and `theme update`.
 - The component registry has **254 entries**: **98 direct install targets** and **156 hidden dependency entries**. `list` shows direct targets; `add` resolves hidden dependencies.
 - `0.4.0-alpha.1` adds `kbd`, `aspect-ratio`, `button-group`, `toggle-group`, `input-group`, `number-input`, `stat-card`, `timeline`, `tree-view`, `qr-code`, `image-viewer`, `chat`, `chat-message`, `chat-input`, and the `auth-01`, `auth-02` and `auth-03` blocks.
 - `0.3.0` added `typed-select`, `command-palette`, `data-picker`, `multi-select`, `tag-input`, `donut-chart`, `radar-chart`, and `radial-chart`.
diff --git a/ShellUI.Tests/MigrateTests.cs b/ShellUI.Tests/MigrateTests.cs
new file mode 100644
index 0000000..73fd534
--- /dev/null
+++ b/ShellUI.Tests/MigrateTests.cs
@@ -0,0 +1,126 @@
+using ShellUI.CLI.Services;
+
+namespace ShellUI.Tests;
+
+public class MigrateTests : IDisposable
+{
+    private readonly string _root = Path.Combine(Path.GetTempPath(), $"migrate-{Guid.NewGuid():N}");
+
+    public MigrateTests()
+    {
+        Directory.CreateDirectory(Path.Combine(_root, "Components", "UI"));
+        Directory.CreateDirectory(Path.Combine(_root, "Components", "Pages"));
+        Directory.CreateDirectory(Path.Combine(_root, "obj"));
+        File.WriteAllText(Path.Combine(_root, "MyApp.csproj"), "<Project Sdk=\"Microsoft.NET.Sdk.Web\"></Project>");
+    }
+
+    public void Dispose()
+    {
+        try { Directory.Delete(_root, recursive: true); } catch (IOException) { }
+    }
+
+    private string Page(string name, string content)
+    {
+        var path = Path.Combine(_root, "Components", "Pages", name);
+        File.WriteAllText(path, content);
+        return path;
+    }
+
+    private MigrationEdit SingleEdit(params string[] components) => Assert.Single(MigrateService.Plan(_root, components).Edits);
+
+    [Fact]
+    public void Input_DropsTheNestedVariantEnum()
+    {
+        Page("Login.razor", "<Input Variant=\"Input.InputVariant.Error\" />\n@code { var v = Input.InputVariant.Default; }");
+
+        var edit = SingleEdit("input");
+
+        Assert.Equal("<Input Variant=\"InputVariant.Error\" />\n@code { var v = InputVariant.Default; }", edit.After);
+    }
+
+    [Fact]
+    public void DatePicker_RenamesSelectedDateButLeavesCalendarAlone()
+    {
+        Page("Booking.razor",
+            "<DatePicker @bind-SelectedDate=\"_date\" @bind-SelectedDate:after=\"Save\" />\n" +
+            "<DatePicker SelectedDate=\"_other\"\n            SelectedDateChanged=\"OnPicked\" Placeholder=\"a > b\" />\n" +
+            "<Calendar @bind-SelectedDate=\"_day\" />");
+
+        var edit = SingleEdit("date-picker");
+
+        Assert.Equal(
+            "<DatePicker @bind-Value=\"_date\" @bind-Value:after=\"Save\" />\n" +
+            "<DatePicker Value=\"_other\"\n            ValueChanged=\"OnPicked\" Placeholder=\"a > b\" />\n" +
+            "<Calendar @bind-SelectedDate=\"_day\" />", edit.After);
+    }
+
+    [Fact]
+    public void TimePicker_RenamesSelectedTime()
+    {
+        Page("Alarm.razor", "<TimePicker @bind-SelectedTime=\"_time\" Step=\"15\" />");
+
+        Assert.Equal("<TimePicker @bind-Value=\"_time\" Step=\"15\" />", SingleEdit("time-picker").After);
+    }
+
+    [Fact]
+    public void Pagination_RenamesOnPageChangeUnlessCurrentPageIsBound()
+    {
+        Page("List.razor",
+            "<Pagination CurrentPage=\"_page\" TotalPages=\"9\" OnPageChange=\"Load\" />\n" +
+            "<Pagination @bind-CurrentPage=\"_page\" OnPageChange=\"Log\" />");
+
+        var edit = SingleEdit("pagination");
+
+        Assert.Equal(
+            "<Pagination CurrentPage=\"_page\" TotalPages=\"9\" CurrentPageChanged=\"Load\" />\n" +
+            "<Pagination @bind-CurrentPage=\"_page\" OnPageChange=\"Log\" />", edit.After);
+    }
+
+    [Fact]
+    public void Plan_SkipsInstalledComponentsAndBuildOutput()
+    {
+        File.WriteAllText(Path.Combine(_root, "Components", "UI", "Input.razor"), "Input.InputVariant.Error");
+        File.WriteAllText(Path.Combine(_root, "obj", "Generated.cs"), "Input.InputVariant.Error");
+        var page = Page("Form.razor", "Input.InputVariant.Error");
+
+        var plan = MigrateService.Plan(_root);
+
+        Assert.Equal(page, Assert.Single(plan.Edits).Path);
+    }
+
+    [Fact]
+    public void Plan_WithNoComponentsRunsEveryMigrationAndListsWhatItApplied()
+    {
+        Page("All.razor", "<TimePicker SelectedTime=\"_t\" />\n<Input Variant=\"Input.InputVariant.Error\" />");
+
+        var edit = SingleEdit();
+
+        Assert.Equal(2, edit.Applied.Count);
+        Assert.Equal("<TimePicker Value=\"_t\" />\n<Input Variant=\"InputVariant.Error\" />", edit.After);
+    }
+
+    [Fact]
+    public void Calendar_FlagsHandlersThatTakeADateTime()
+    {
+        var page = Page("Plan.razor",
+            "<Calendar SelectedDateChanged=\"OnDay\" />\n@code {\n    void OnDay(DateTime day) { }\n    void Other(DateTime d) { }\n}");
+
+        var plan = MigrateService.Plan(_root);
+
+        Assert.Empty(plan.Edits);
+        var note = Assert.Single(plan.Notes);
+        Assert.Equal(page, note.Path);
+        Assert.Equal(3, note.Line);
+    }
+
+    [Fact]
+    public void Plan_IsEmptyForAnUpToDateApp()
+    {
+        Page("Fine.razor", "<DatePicker @bind-Value=\"_d\" />\n<Calendar SelectedDateChanged=\"OnDay\" />\n@code { void OnDay(DateTime? d) { } }");
+
+        var plan = MigrateService.Plan(_root);
+
+        Assert.Empty(plan.Edits);
+        Assert.Empty(plan.Notes);
+    }
+}
diff --git a/docs/CLI_SYNTAX.md b/docs/CLI_SYNTAX.md
index 396d15f..ded3ded 100644
--- a/docs/CLI_SYNTAX.md
+++ b/docs/CLI_SYNTAX.md
@@ -22,6 +22,7 @@ shellui list [--installed|--available]
 shellui remove <name...>
 shellui update [name...] [--all] [--force]
 shellui doctor
+shellui migrate [name...] [--dry-run] [--yes]
 shellui theme init <url-or-id> [--force] [--style <style>] [--tailwind standalone|npm] [--yes] [--dashboard 01|02|none] [--replace-layout]
 shellui theme apply <url-or-id> [--emit-override <path>]
 shellui theme update
@@ -168,7 +169,7 @@ Names are separated by spaces. With no names, or with `--all`, every installed c
 - **Your changes are kept.** `shellui.json` records a hash of each file as the CLI wrote it. If a file has changed since, `update` skips it and says so; `--force` overwrites it. Files installed by a CLI older than 0.4.0-alpha.2 have no hash, so for those `update` keeps the blocks apps are meant to edit (`app-sidebar`, `sidebar-account`, the `dashboard-*` and `auth-*` layouts) when they differ from the template, and rewrites everything else.
 - **New dependencies are installed.** When a component gained dependencies since you installed it (for example `tabs` now needs `tab-models`), `update` adds them, with their NuGet packages and `_Imports.razor` usings, the same way `add` does.
 
-`update` has no diff or merge. Commit before updating so you can review the changes.
+`update` has no diff or merge. Commit before updating so you can review the changes. When a template's API changed, run `shellui migrate` afterwards to update your pages.
 
 ## `doctor`
 
@@ -188,6 +189,29 @@ shellui doctor
 
 It exits with code 1 when it finds a problem, so it can run in CI. Warnings, such as a stale `app.css`, don't change the exit code. In a Razor class library it skips the host page checks, which apply to each app that uses the library.
 
+## `migrate`
+
+Rewrites your own pages for template API changes listed in the release notes, after `shellui update` has replaced the components:
+
+```bash
+shellui migrate --dry-run
+shellui migrate
+shellui migrate date-picker pagination
+shellui migrate --yes
+```
+
+It reads the project's `.razor` and `.cs` files (not the installed components under `ComponentsPath`, or `bin`, `obj` and `node_modules`), shows each changed line, and asks before writing. `--dry-run` only shows the changes; `--yes` writes them without asking, and is required when the terminal isn't interactive. With no names it runs every migration.
+
+| Name | Change |
+|---|---|
+| `input` | `Input.InputVariant.Error` → `InputVariant.Error` (0.4.0-alpha.3) |
+| `date-picker` | `SelectedDate`, `SelectedDateChanged` and `@bind-SelectedDate` → `Value`, `ValueChanged` and `@bind-Value`, on `<DatePicker>` only (0.4.0-alpha.3) |
+| `time-picker` | the same for `<TimePicker>`'s `SelectedTime` (0.4.0-alpha.3) |
+| `pagination` | `OnPageChange` → `CurrentPageChanged`, except on a tag that already uses `@bind-CurrentPage` (0.4.0-alpha.3) |
+| `calendar` | Reports handlers of `Calendar.SelectedDateChanged` that take a `DateTime`; they need a `DateTime?` since 0.4.0-alpha.1. Nothing is rewritten. |
+
+Commit first, then build the app afterwards.
+
 ## `theme`
 
 The theme commands fetch a public tweakcn theme by URL or theme ID and write its CSS variables into the project.
diff --git a/src/ShellUI.CLI/Program.cs b/src/ShellUI.CLI/Program.cs
index 93a1a43..860b978 100644
--- a/src/ShellUI.CLI/Program.cs
+++ b/src/ShellUI.CLI/Program.cs
@@ -25,6 +25,7 @@ static async Task<int> Main(string[] args)
         rootCommand.AddCommand(CreateUpdateCommand());
         rootCommand.AddCommand(CreateThemeCommand());
         rootCommand.AddCommand(CreateDoctorCommand());
+        rootCommand.AddCommand(CreateMigrateCommand());
 
         return await rootCommand.InvokeAsync(args);
     }
@@ -286,6 +287,43 @@ static Command CreateDoctorCommand()
         return command;
     }
 
+    static Command CreateMigrateCommand()
+    {
+        var command = new Command("migrate", "Rewrite your pages for template API changes, showing a diff and asking first");
+
+        var componentsArg = new Argument<string[]>(
+            "components",
+            $"Component(s) to migrate (empty = all): {string.Join(", ", MigrateService.Components)}")
+        {
+            Arity = ArgumentArity.ZeroOrMore
+        };
+        command.AddArgument(componentsArg);
+
+        var dryRunOption = new Option<bool>("--dry-run", "Show the changes without writing them");
+        command.AddOption(dryRunOption);
+
+        var yesOption = new Option<bool>("--yes", "Write the changes without asking");
+        command.AddOption(yesOption);
+
+        command.SetHandler(context =>
+        {
+            try
+            {
+                context.ExitCode = MigrateService.Run(
+                    context.ParseResult.GetValueForArgument(componentsArg),
+                    context.ParseResult.GetValueForOption(dryRunOption),
+                    context.ParseResult.GetValueForOption(yesOption));
+            }
+            catch (Exception ex)
+            {
+                AnsiConsole.MarkupLine($"[red]Error:[/] {Markup.Escape(ex.Message)}");
+                context.ExitCode = 1;
+            }
+        });
+
+        return command;
+    }
+
     static Command CreateListCommand()
     {
         var command = new Command("list", "List available components");
diff --git a/src/ShellUI.CLI/Services/MigrateService.cs b/src/ShellUI.CLI/Services/MigrateService.cs
new file mode 100644
index 0000000..15245cd
--- /dev/null
+++ b/src/ShellUI.CLI/Services/MigrateService.cs
@@ -0,0 +1,201 @@
+using System.Text;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using ShellUI.Core.Models;
+using Spectre.Console;
+
+namespace ShellUI.CLI.Services;
+
+public record MigrationEdit(string Path, string Before, string After, IReadOnlyList<string> Applied);
+
+public record MigrationNote(string Path, int Line, string Message);
+
+public record MigrationPlan(IReadOnlyList<MigrationEdit> Edits, IReadOnlyList<MigrationNote> Notes);
+
+// Rewrites an app's own .razor and .cs files for template API changes listed in the release notes.
+public static class MigrateService
+{
+    private record Migration(string Component, string Summary, Func<string, string> Rewrite);
+
+    private static readonly Migration[] Migrations =
+    {
+        new("input", "Input.InputVariant.X → InputVariant.X (0.4.0-alpha.3)",
+            text => text.Replace("Input.InputVariant.", "InputVariant.")),
+        new("date-picker", "DatePicker SelectedDate → Value (0.4.0-alpha.3)",
+            text => RewriteTags(text, "DatePicker", tag => RenameParameter(tag, "SelectedDate", "Value"))),
+        new("time-picker", "TimePicker SelectedTime → Value (0.4.0-alpha.3)",
+            text => RewriteTags(text, "TimePicker", tag => RenameParameter(tag, "SelectedTime", "Value"))),
+        new("pagination", "Pagination OnPageChange → CurrentPageChanged (0.4.0-alpha.3)",
+            text => RewriteTags(text, "Pagination", tag =>
+                // @bind-CurrentPage already sets CurrentPageChanged, so a tag with both can't be renamed.
+                Regex.IsMatch(tag, @"@bind-CurrentPage\b") ? tag : Regex.Replace(tag, @"(?<=\s)OnPageChange(?=\s*=)", "CurrentPageChanged"))),
+    };
+
+    // calendar only reports handlers to fix by hand.
+    public static IReadOnlyList<string> Components => Migrations.Select(m => m.Component).Append("calendar").Distinct().ToList();
+
+    public static int Run(string[] components, bool dryRun, bool yes)
+    {
+        var unknown = components.Where(c => !Components.Contains(c, StringComparer.OrdinalIgnoreCase)).ToList();
+        if (unknown.Count > 0)
+        {
+            AnsiConsole.MarkupLine($"[red]No migrations for:[/] {Markup.Escape(string.Join(", ", unknown))}. Migrations exist for {Markup.Escape(string.Join(", ", Components))}.");
+            return 1;
+        }
+
+        var root = Directory.GetCurrentDirectory();
+        var plan = Plan(root, components);
+
+        foreach (var edit in plan.Edits)
+        {
+            AnsiConsole.MarkupLine($"[bold]{Markup.Escape(Path.GetRelativePath(root, edit.Path))}[/] [dim]({Markup.Escape(string.Join("; ", edit.Applied))})[/]");
+            foreach (var line in Diff(edit.Before, edit.After))
+                AnsiConsole.MarkupLine(line.StartsWith('-') ? $"[red]{Markup.Escape(line)}[/]" : $"[green]{Markup.Escape(line)}[/]");
+            AnsiConsole.MarkupLine("");
+        }
+        foreach (var note in plan.Notes)
+            AnsiConsole.MarkupLine($"[yellow]![/] {Markup.Escape(Path.GetRelativePath(root, note.Path))}:{note.Line} {Markup.Escape(note.Message)}");
+
+        if (plan.Edits.Count == 0)
+        {
+            AnsiConsole.MarkupLine(plan.Notes.Count == 0 ? "[green]Nothing to migrate.[/]" : "[green]Nothing to rewrite.[/] Check the notes above by hand.");
+            return 0;
+        }
+        if (dryRun)
+        {
+            AnsiConsole.MarkupLine($"[dim]Dry run: {plan.Edits.Count} file(s) would change.[/]");
+            return 0;
+        }
+        if (!yes && !AnsiConsole.Profile.Capabilities.Interactive)
+        {
+            AnsiConsole.MarkupLine("[yellow]Not an interactive terminal, so nothing was written.[/] Run again with --yes to write the changes.");
+            return 1;
+        }
+        if (!yes && !AnsiConsole.Confirm($"Write these changes to {plan.Edits.Count} file(s)?", false))
+        {
+            AnsiConsole.MarkupLine("[dim]Nothing written.[/]");
+            return 0;
+        }
+
+        foreach (var edit in plan.Edits)
+            File.WriteAllText(edit.Path, edit.After);
+        AnsiConsole.MarkupLine($"[green]Migrated {plan.Edits.Count} file(s).[/] Build the app to check.");
+        return 0;
+    }
+
+    public static MigrationPlan Plan(string root, IEnumerable<string>? components = null)
+    {
+        var wanted = components?.ToList() is { Count: > 0 } list
+            ? Migrations.Where(m => list.Contains(m.Component, StringComparer.OrdinalIgnoreCase)).ToList()
+            : Migrations.ToList();
+        var checkCalendar = components?.Any() != true || components.Contains("calendar", StringComparer.OrdinalIgnoreCase);
+
+        var edits = new List<MigrationEdit>();
+        var notes = new List<MigrationNote>();
+        foreach (var path in SourceFiles(root))
+        {
+            var before = File.ReadAllText(path);
+            var after = before;
+            var applied = new List<string>();
+            foreach (var migration in wanted)
+            {
+                var next = migration.Rewrite(after);
+                if (next == after) continue;
+                after = next;
+                applied.Add(migration.Summary);
+            }
+            if (after != before) edits.Add(new MigrationEdit(path, before, after, applied));
+            if (checkCalendar) notes.AddRange(CalendarHandlerNotes(path, after));
+        }
+        return new MigrationPlan(edits, notes);
+    }
+
+    // The app's own sources: not the installed components (update rewrites those) or build output.
+    private static IEnumerable<string> SourceFiles(string root)
+    {
+        var componentsPath = "Components/UI";
+        var configPath = Path.Combine(root, "shellui.json");
+        if (File.Exists(configPath))
+        {
+            try { componentsPath = JsonSerializer.Deserialize<ShellUIConfig>(File.ReadAllText(configPath))?.ComponentsPath ?? componentsPath; }
+            catch (JsonException) { }
+        }
+        var skip = new[] { "bin", "obj", "node_modules", ".shellui", ".git" };
+        var componentsDir = Path.GetFullPath(Path.Combine(root, componentsPath)) + Path.DirectorySeparatorChar;
+
+        return Directory.EnumerateFiles(root, "*.*", SearchOption.AllDirectories)
+            .Where(p => p.EndsWith(".razor", StringComparison.OrdinalIgnoreCase) || p.EndsWith(".cs", StringComparison.OrdinalIgnoreCase))
+            .Where(p => !Path.GetRelativePath(root, p).Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar).Any(part => skip.Contains(part, StringComparer.OrdinalIgnoreCase)))
+            .Where(p => !Path.GetFullPath(p).StartsWith(componentsDir, StringComparison.OrdinalIgnoreCase))
+            .OrderBy(p => p, StringComparer.Ordinal);
+    }
+
+    // Applies rewrite to every <Name …> opening tag, scanning to the closing > outside quotes.
+    internal static string RewriteTags(string text, string name, Func<string, string> rewrite)
+    {
+        var result = new StringBuilder();
+        var position = 0;
+        foreach (Match match in Regex.Matches(text, $@"<{name}(?=[\s/>])"))
+        {
+            if (match.Index < position) continue;
+            var end = TagEnd(text, match.Index + match.Length);
+            result.Append(text, position, match.Index - position);
+            result.Append(rewrite(text[match.Index..end]));
+            position = end;
+        }
+        result.Append(text, position, text.Length - position);
+        return result.ToString();
+    }
+
+    private static int TagEnd(string text, int start)
+    {
+        char? quote = null;
+        for (var i = start; i < text.Length; i++)
+        {
+            var c = text[i];
+            if (quote != null) { if (c == quote) quote = null; }
+            else if (c is '"' or '\'') quote = c;
+            else if (c == '>') return i + 1;
+        }
+        return text.Length;
+    }
+
+    // Renames Old, OldChanged, @bind-Old and @bind-Old:after (and so on) to the new name.
+    private static string RenameParameter(string tag, string oldName, string newName) =>
+        Regex.Replace(tag, $@"(?<=\s)(@bind-)?{oldName}(Changed)?(?=[\s:=])", m => m.Groups[1].Value + newName + m.Groups[2].Value);
+
+    // Calendar.SelectedDateChanged became EventCallback<DateTime?> in 0.4.0-alpha.1; a handler taking DateTime no longer compiles.
+    private static IEnumerable<MigrationNote> CalendarHandlerNotes(string path, string text)
+    {
+        var handlers = new HashSet<string>();
+        RewriteTags(text, "Calendar", tag =>
+        {
+            foreach (Match m in Regex.Matches(tag, @"(?<=\s)SelectedDateChanged\s*=\s*""@?(\w+)"""))
+                handlers.Add(m.Groups[1].Value);
+            return tag;
+        });
+        foreach (var handler in handlers)
+        {
+            foreach (Match m in Regex.Matches(text, $@"\b{handler}\s*\(\s*DateTime\s+\w+"))
+            {
+                var line = text[..m.Index].Count(c => c == '\n') + 1;
+                yield return new MigrationNote(path, line, $"{handler} handles Calendar.SelectedDateChanged with a DateTime; it now needs a DateTime? (0.4.0-alpha.1).");
+            }
+        }
+    }
+
+    // Changed lines only, prefixed - and +, with their line numbers.
+    private static IEnumerable<string> Diff(string before, string after)
+    {
+        var a = before.Split('\n');
+        var b = after.Split('\n');
+        for (var i = 0; i < Math.Max(a.Length, b.Length); i++)
+        {
+            var left = i < a.Length ? a[i].TrimEnd('\r') : null;
+            var right = i < b.Length ? b[i].TrimEnd('\r') : null;
+            if (left == right) continue;
+            if (left != null) yield return $"-{i + 1,5}: {left.Trim()}";
+            if (right != null) yield return $"+{i + 1,5}: {right.Trim()}";
+        }
+    }
+}