The change in 1.0.154.46 to fix Hotmail caused a problem for users in Incognito mode trying to access sites which depend on the User-Agent header. This header identifies the type of browser making the request and should be part of every request, even in Incognito mode. This issue is now fixed. There is also a security fix for a bug (analogous to CVE-2007-3670) where command line arguments could be injected and executed by getting a user to click a link in certain other browsers.