Is there any released documentation thus far? For example, can we remove the pointless /topic/ section? It's not a directory/leads to nothing - there's no real use for it.

Friendly URLs are configurable in 4.0.

I just installed IPB 4 Beta and url arent working, how can fix that?

Redirection error

Please post in the appropriate peer help forums. This is a feedback forum. :)

Can someone tell me if the url structure changed between IPS 3.x and 4.x?

The URL structure for some areas has changed, but old URLs will 301 redirect to the new location.