diff --git a/packages/playground/big-component-library-kit/package.json b/packages/playground/big-component-library-kit/package.json
index a38588a9f..70022e1b9 100644
--- a/packages/playground/big-component-library-kit/package.json
+++ b/packages/playground/big-component-library-kit/package.json
@@ -10,7 +10,7 @@
     "check:watch": "svelte-kit sync && svelte-check --tsconfig ./jsconfig.json --watch"
   },
   "devDependencies": {
-    "@sveltejs/adapter-auto": "3.3.1",
+    "@sveltejs/adapter-auto": "4.0.0",
     "@sveltejs/kit": "^2.16.0",
     "@sveltejs/vite-plugin-svelte": "workspace:^",
     "carbon-components-svelte": "^0.87.1",
diff --git a/packages/playground/kit-demo-app/package.json b/packages/playground/kit-demo-app/package.json
index 9351c5180..ac19778a2 100644
--- a/packages/playground/kit-demo-app/package.json
+++ b/packages/playground/kit-demo-app/package.json
@@ -12,7 +12,7 @@
   "devDependencies": {
     "@fontsource/fira-mono": "^5.1.1",
     "@neoconfetti/svelte": "^2.2.1",
-    "@sveltejs/adapter-auto": "^3.3.1",
+    "@sveltejs/adapter-auto": "^4.0.0",
     "@sveltejs/kit": "^2.16.0",
     "@sveltejs/vite-plugin-svelte": "workspace:^",
     "svelte": "^5.19.0",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f6d52e74a..b8b365f90 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -659,8 +659,8 @@ importers:
   packages/playground/big-component-library-kit:
     devDependencies:
       '@sveltejs/adapter-auto':
-        specifier: 3.3.1
-        version: 3.3.1(@sveltejs/kit@2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1)))
+        specifier: 4.0.0
+        version: 4.0.0(@sveltejs/kit@2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1)))
       '@sveltejs/kit':
         specifier: ^2.16.0
         version: 2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1))
@@ -744,8 +744,8 @@ importers:
         specifier: ^2.2.1
         version: 2.2.1
       '@sveltejs/adapter-auto':
-        specifier: ^3.3.1
-        version: 3.3.1(@sveltejs/kit@2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1)))
+        specifier: ^4.0.0
+        version: 4.0.0(@sveltejs/kit@2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1)))
       '@sveltejs/kit':
         specifier: ^2.16.0
         version: 2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1))
@@ -1551,8 +1551,8 @@ packages:
     peerDependencies:
       eslint: '>=8.40.0'
 
-  '@sveltejs/adapter-auto@3.3.1':
-    resolution: {integrity: sha512-5Sc7WAxYdL6q9j/+D0jJKjGREGlfIevDyHSQ2eNETHcB1TKlQWHcAo8AS8H1QdjNvSXpvOwNjykDUHPEAyGgdQ==}
+  '@sveltejs/adapter-auto@4.0.0':
+    resolution: {integrity: sha512-kmuYSQdD2AwThymQF0haQhM8rE5rhutQXG4LNbnbShwhMO4qQGnKaaTy+88DuNSuoQDi58+thpq8XpHc1+oEKQ==}
     peerDependencies:
       '@sveltejs/kit': ^2.0.0
 
@@ -4323,7 +4323,7 @@ snapshots:
       eslint-visitor-keys: 4.2.0
       espree: 10.3.0
 
-  '@sveltejs/adapter-auto@3.3.1(@sveltejs/kit@2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1)))':
+  '@sveltejs/adapter-auto@4.0.0(@sveltejs/kit@2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1)))':
     dependencies:
       '@sveltejs/kit': 2.16.0(@sveltejs/vite-plugin-svelte@packages+vite-plugin-svelte)(svelte@5.19.0)(vite@6.0.9(@types/node@20.11.5)(sass@1.83.4)(stylus@0.64.0)(yaml@2.6.1))
       import-meta-resolve: 4.1.0