Hello, on one forum i want to uninstall the SEO, but how can i do it in that way, that SEO links will still work, or i cant?

You have to leave your .htaccess as it is !

Well, the only problem with what you want to do, and rather it is or not a good idea is another debate, is you'd maintain duplicate content if you allow two kind of urls.

And this is not good.

You'd need to http 301 redirect rewritten url to vanilla ones to do so properly.

This is fairly easy, would just require to mod your .htaccess a bit.

Now the real question is why would you want to do this ?

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