diff --git a/Api.SeaHavenIndustries/Middleware/LegacyDeprecationMiddleware.cs b/Api.SeaHavenIndustries/Middleware/LegacyDeprecationMiddleware.cs
new file mode 100644
index 0000000..0e2ccb6
--- /dev/null
+++ b/Api.SeaHavenIndustries/Middleware/LegacyDeprecationMiddleware.cs
@@ -0,0 +1,57 @@
+using Api.SeaHavenIndustries.Options;
+using Microsoft.Extensions.Options;
+
+namespace Api.SeaHavenIndustries.Middleware
+{
+    /// <summary>Adds Sunset/Deprecation headers to legacy WorkOrder REST routes.</summary>
+    public class LegacyDeprecationMiddleware
+    {
+        private static readonly HashSet<string> LegacyPathSegments = new(StringComparer.OrdinalIgnoreCase)
+        {
+            "GetWorkOrderList",
+            "AddWorkorder",
+            "EditWorkorder",
+            "ChangeStatus",
+            "ChangeAssignment",
+            "DeleteWorkorder",
+            "GetWorkorderById"
+        };
+
+        private readonly RequestDelegate _next;
+        private readonly LegacyEndpointOptions _options;
+
+        public LegacyDeprecationMiddleware(RequestDelegate next, IOptions<LegacyEndpointOptions> options)
+        {
+            _next = next;
+            _options = options.Value;
+        }
+
+        public async Task InvokeAsync(HttpContext context)
+        {
+            if (_options.DeprecationEnabled)
+            {
+                var path = context.Request.Path.Value ?? "";
+                var isLegacyWo = (path.Contains("/WorkOrder", StringComparison.OrdinalIgnoreCase)
+                        || path.Contains("/workorders", StringComparison.OrdinalIgnoreCase))
+                    && LegacyPathSegments.Any(seg => path.Contains(seg, StringComparison.OrdinalIgnoreCase));
+
+                if (isLegacyWo)
+                {
+                    context.Response.OnStarting(() =>
+                    {
+                        context.Response.Headers["Deprecation"] = "true";
+                        if (!string.IsNullOrWhiteSpace(_options.SunsetDate)
+                            && DateTimeOffset.TryParse(_options.SunsetDate, out var sunset))
+                        {
+                            context.Response.Headers["Sunset"] = sunset.UtcDateTime.ToString("r");
+                        }
+                        context.Response.Headers["Link"] = "</api/workorders/board>; rel=\"successor-version\"";
+                        return Task.CompletedTask;
+                    });
+                }
+            }
+
+            await _next(context);
+        }
+    }
+}
diff --git a/Api.SeaHavenIndustries/Program.cs b/Api.SeaHavenIndustries/Program.cs
index e897f24..c85271b 100644
--- a/Api.SeaHavenIndustries/Program.cs
+++ b/Api.SeaHavenIndustries/Program.cs
@@ -1,5 +1,6 @@
-using Api.SeaHavenIndustries.Helper;
+using Api.SeaHavenIndustries.Helper;
 using Api.SeaHavenIndustries.HostedServices;
+using Api.SeaHavenIndustries.Middleware;
 using Api.SeaHavenIndustries.Options;
 using Data.SeaHavenIndustries;
 using Microsoft.AspNetCore.Authentication.JwtBearer;
@@ -151,6 +152,7 @@ if (!app.Environment.IsDevelopment())
     app.UseHttpsRedirection();
 app.UseStaticFiles();
 app.UseCors();
+app.UseMiddleware<LegacyDeprecationMiddleware>();
 app.UseAuthentication();
 app.UseAuthorization();
 
@@ -213,4 +215,3 @@ app.MapControllers();
 //}
 
 app.Run();
-
diff --git a/SeaHavenIndustries/Data/Services/WorkorderService.cs b/SeaHavenIndustries/Data/Services/WorkorderService.cs
index f616377..2e18cf2 100644
--- a/SeaHavenIndustries/Data/Services/WorkorderService.cs
+++ b/SeaHavenIndustries/Data/Services/WorkorderService.cs
@@ -22,14 +22,22 @@ namespace SeaHavenIndustries.Data.Services
         private UserManager<ApplicationUser> _userManager;
         private UploadFileHp _uploadFileHelper;
         private readonly SendMessage _sendemail;
+        private readonly BlazorWorkOrderSunsetGuard _sunsetGuard;
 
-        public WorkorderService(SendMessage sendemail, ApplicationDbContext context, IHttpContextAccessor httpContextAccessor, UserManager<ApplicationUser> userManager, UploadFileHp uploadFileHelper)
+        public WorkorderService(
+            SendMessage sendemail,
+            ApplicationDbContext context,
+            IHttpContextAccessor httpContextAccessor,
+            UserManager<ApplicationUser> userManager,
+            UploadFileHp uploadFileHelper,
+            BlazorWorkOrderSunsetGuard sunsetGuard)
         {
             _context = context;
             _httpContextAccessor = httpContextAccessor;
             _userManager = userManager;
             _uploadFileHelper = uploadFileHelper;
             _sendemail = sendemail;
+            _sunsetGuard = sunsetGuard;
         }
         public async Task<List<WorkOrder>> Getworkorder()
         {
@@ -178,6 +186,7 @@ namespace SeaHavenIndustries.Data.Services
         }
         public async Task<string> Addworkorder(WorkOrder model, List<FileUploadViewModel> files)
         {
+            _sunsetGuard.ThrowIfMutationsBlocked();
             try
             {
                 _context.ChangeTracker.Clear();
@@ -425,6 +434,7 @@ namespace SeaHavenIndustries.Data.Services
         }
         public async Task<string> Deleteworkorder(int id)
         {
+            _sunsetGuard.ThrowIfMutationsBlocked();
             _context.ChangeTracker.Clear();
 
             try
diff --git a/SeaHavenIndustries/Helper/BlazorWorkOrderSunsetGuard.cs b/SeaHavenIndustries/Helper/BlazorWorkOrderSunsetGuard.cs
new file mode 100644
index 0000000..5c7bbf8
--- /dev/null
+++ b/SeaHavenIndustries/Helper/BlazorWorkOrderSunsetGuard.cs
@@ -0,0 +1,26 @@
+using Microsoft.Extensions.Options;
+using SeaHavenIndustries.Options;
+
+namespace SeaHavenIndustries.Helper
+{
+    public class BlazorWorkOrderSunsetGuard
+    {
+        private readonly BlazorWorkOrderSunsetOptions _options;
+
+        public BlazorWorkOrderSunsetGuard(IOptions<BlazorWorkOrderSunsetOptions> options)
+        {
+            _options = options.Value;
+        }
+
+        public bool IsSunsetEnabled => _options.Enabled;
+
+        public string ShocBaseUrl => _options.ShocBaseUrl.TrimEnd('/');
+
+        public void ThrowIfMutationsBlocked()
+        {
+            if (_options.Enabled)
+                throw new InvalidOperationException(
+                    "Work Orders module has moved to SHOC. Editing via Blazor is disabled.");
+        }
+    }
+}
diff --git a/SeaHavenIndustries/Options/BlazorWorkOrderSunsetOptions.cs b/SeaHavenIndustries/Options/BlazorWorkOrderSunsetOptions.cs
new file mode 100644
index 0000000..e368d9f
--- /dev/null
+++ b/SeaHavenIndustries/Options/BlazorWorkOrderSunsetOptions.cs
@@ -0,0 +1,11 @@
+namespace SeaHavenIndustries.Options
+{
+    public class BlazorWorkOrderSunsetOptions
+    {
+        public const string SectionName = "BlazorWorkOrderSunset";
+
+        public bool Enabled { get; set; }
+
+        public string ShocBaseUrl { get; set; } = "https://shoc.seahaven.com";
+    }
+}
diff --git a/SeaHavenIndustries/Program.cs b/SeaHavenIndustries/Program.cs
index 5450abf..48b76c3 100644
--- a/SeaHavenIndustries/Program.cs
+++ b/SeaHavenIndustries/Program.cs
@@ -77,6 +77,9 @@ builder.Services.AddScoped<UploadFileHp>();
 builder.Services.AddScoped<NorthwindService>();
 builder.Services.AddScoped<SendMessage>();
 builder.Services.AddScoped<PdfService>();
+builder.Services.Configure<SeaHavenIndustries.Options.BlazorWorkOrderSunsetOptions>(
+    builder.Configuration.GetSection(SeaHavenIndustries.Options.BlazorWorkOrderSunsetOptions.SectionName));
+builder.Services.AddSingleton<BlazorWorkOrderSunsetGuard>();
 
 builder.Services.AddSession(options =>
 {