I've just upgraded from v8 to v9.1.1 (on the way to the latest version). I have two sites, one of which uses .aspx extensions on URLs, and the other does not. The .aspx one is returning 404 errors for all pages except /Default.aspx.
I've turned on failed request tracing in IIS. On a pre-upgrade site, I can see that AdvancedUrlRewriter is doing a URL_CHANGED from the requested URL to /Default.aspx?TabId=xxx. On the post-upgrade site, it is not doing this.
Why is AdvancedUrlRewriter behaving differently in v9, and is there a setting I can change to fix it?