TYPO3 Core

With TYPO3 v9 the site configuration with its own 404 handling comes in. But it has a drawback: When you have a site configuration with multiple languages which results in URLs like /de/, /en/, /fr/ and now a URL which starts with /abc a redirect (307) to the default language is performed.

This is not optimal because of the following reasons:

• Under SEO aspects: it seems to a search engine, that the old URL can be still valid (it's only a temporary redirect) so the URL can still be inside the search results.
• Under UX aspects: The user clicks on a link, comes to the home page and doesn't find what he wants, and leaves (frustrated)
• If you link to that page (from another website) which has this behaviour, you get no information from link validators, that this page has gone (and cannot update or remove the link)

I also had the discussion some time ago, that it is not known, which language the 404 page should be shown. If I want to have this, I should use the default language under the path / and not /de. This is not always possible (we use / to determine the browser language and make a redirect to the according website language).

It is the better alternative to have a 404 page in the default language instead of the redirect.