Some of you may have signed on to Xbox Live recently and received a prompt for an update. This is a behind-the-scenes update, containing improvements on existing features and foundations for new ones, so there are no visible changes. Not everyone has received this yet; according to these tweets from Major Nelson, some will receive the update this week while everyone else will get it next week. Like all updates, it will occur as soon as you connect to Xbox Live and will require a few minutes to download. The update is mandatory to continue using Live, but you'll be back to playing your favorite XBLA games in no time anyway.