diff --git a/src/content/docs/en/guides/upgrade-to/v6.mdx b/src/content/docs/en/guides/upgrade-to/v6.mdx
index 59b159dff19e9..906276376007a 100644
--- a/src/content/docs/en/guides/upgrade-to/v6.mdx
+++ b/src/content/docs/en/guides/upgrade-to/v6.mdx
@@ -611,6 +611,18 @@ export default defineConfig({
 })
 ```
 
+If you are using manual routing, you may also need to update your middleware configuration:
+
+```js title="src/middleware.js" del={4} ins={5}
+import { middleware } from "astro:i18n"; // Astro's own i18n routing config
+
+export const onRequest = middleware({
+  prefixDefaultLocale: false,
+  prefixDefaultLocale: true,
+  redirectToDefaultLocale: true,
+})
+```
+
 <ReadMore>Learn more about [Internationalization routing](/en/guides/internationalization/#routing).</ReadMore>
 
 ### Changed: `<script>` and `<style>` tags are rendered in the order they are defined