Sometime during the day tomorrow (Tuesday, July 19th) when you sign in to Xbox LIVE youll receive a prompt to accept a mandatory system update. If you are signed into LIVE already, you may be signed out and asked to accept the update and youll be back online in a few moments.There are no new features that will show up once your system has been updated.This update is preparation for additional system enhancements coming to Xbox 360 later this year.