diff --git a/database/migrations/2026_04_19_235904_backfill_utls_for_legacy_servers.php b/database/migrations/2026_04_19_235904_backfill_utls_for_legacy_servers.php
new file mode 100644
index 0000000..0222030
--- /dev/null
+++ b/database/migrations/2026_04_19_235904_backfill_utls_for_legacy_servers.php
@@ -0,0 +1,48 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+use Illuminate\Support\Facades\Schema;
+
+// Backfill default utls for legacy vless reality nodes after the uTLS refactor.
+return new class extends Migration
+{
+    public function up(): void
+    {
+        if (!Schema::hasTable('v2_server')) {
+            return;
+        }
+
+        DB::table('v2_server')
+            ->where('type', 'vless')
+            ->orderBy('id')
+            ->chunkById(200, function ($servers) {
+                foreach ($servers as $server) {
+                    $settings = json_decode($server->protocol_settings ?? '', true);
+                    if (!is_array($settings) || (int) ($settings['tls'] ?? 0) != 2) {
+                        continue;
+                    }
+
+                    $existing = $settings['utls'] ?? null;
+                    if (is_array($existing) && ($existing['enabled'] ?? false) === true) {
+                        continue;
+                    }
+
+                    $settings['utls'] = [
+                        'enabled' => true,
+                        'fingerprint' => is_array($existing) && !empty($existing['fingerprint'])
+                            ? $existing['fingerprint']
+                            : 'chrome',
+                    ];
+
+                    DB::table('v2_server')
+                        ->where('id', $server->id)
+                        ->update(['protocol_settings' => json_encode($settings)]);
+                }
+            });
+    }
+
+    public function down(): void
+    {
+    }
+};