UPDATE: The new dashboard version is 2.0.13599.0 & there has been
reports of consoles being banned after the update. Not only that, it appears that the DAE table has changed again as all AP2.5 games do not boot. If you value your Xbox Live & iXtreme, then stay offline until further notice!
UPDATE 2: It has been confirmed that Slim Liteon 9504/0272 drives will be updated (as necessary) and become write-protected.
UPDATE 3 : Xecuter has posted a FAQ detailing the new update. Read it
here.
Yesterday, Major Nelson posted on his blog that a new mandatory system update will be rolling to Xbox Live users everywhere on Tuesday, July 19 2011. (Today) There will not be any new features added to the console but Major Nelson does note that it will prepare your Xbox for future enhancements, whatever they may be.