Create API to notify clients when an update fails

[Andy Matuschak]

Howdy - first, thanks for such a great framework - it has saved a lot of development effort.

My question is straightforward, what delegate is called by the updater if the appcast isn't found or the URL where it is located at times out? I have a case where I normally want to force users to upgrade (the app is a client communicating with a server that need to align their schema versions) but if I can't connect to the server (and get the appcast.xml) the app runs in "disconnected" mode and no upgrade is required. Is there a callback(delegate) that tells me that Sparkle looked for but didn't find the appcast at all (like didNotFinishLoadingAppcast or didNotFindAppcast)?

Thanks!