Pertains to 1.1-dev build #52.

When in the Page History of an older version is selected (i.e. clicking on a link in the first column [e.g. "v. 1"]), then the user is required to be logged in. After logging in the message "Not Permitted" and "You are not permitted to perform this operation." is displayed.

Is there a new permission in Confluence? If that is the case then not allowing registered users to view older versions is an inappropriate default, as this even applies to versions which the user himself created. Further note that diffing two page versions is allowed.