Kernel

Version 2.0.13146.0 is currently the latest public version.

You can check your kernel version in "System -> Console Settings -> System Info". The line at the bottom contains your kernel version in the format K:2.0.XXXX.0, where XXXX is your kernel version.

Version	Release Date	Comment
2.0.1888.0	November 22, 2005	Original shipped version
2.0.2241.0	November 22, 2005	Update available at product launch
2.0.2255.0	January 30, 2006	Blocklist for certain .xex file
2.0.2258.0	March 2, 2006
2.0.2858.0	June 05, 2006
2.0.4532.0	October 31, 2006	New identifier X with value 2BB7-8E09-0188-D795
2.0.4548.0	November 30, 2006
2.0.4552.0	January 9, 2007	Fix unsigned code vulnerability
2.0.5759.0	May 9, 2007	Added Instant Messaging
2.0.5766.0	August 7, 2007	Wireless guitars Yet unknown fixes
2.0.6683.0	December 4, 2007	Fall Update. Timing attack works (dependant on CB).
2.0.6717.0	August 6, 2008	Scalability Updates
2.0.7357.0	November 19, 2008	New dashboard ("NXE")
2.0.7363.0	February 3, 2009	HDMI audio fix
2.0.7371.0	April 2, 2009	Fixes Xbox Live issues
2.0.8495.0	July, 2009	Update preview
2.0.8496.0	July 31, 2009	Update preview (second)
2.0.8498.0	August 11, 2009	Public Dashboard Released
2.0.8507.0	September 23, 2009	Preparation for newer dash
2.0.8955.0	October 28, 2009	Blocking 3rd party storage devices, adding WPA2 support for wireless adapters
2.0.9199.0	April 6, 2010	USB storage support added
2.0.12611.0	November 1, 2010	GUI upgrade for Kinect release, ESPN on Xbox LIVE released
2.0.12625.0	January 19, 2011	Adds further anti-piracy 2.5 scheme to more popular games Halo: Reach, Call of Duty: Black Ops and Call of Duty: Modern Warfare 2. Fixes ‘Boot to Disc’ option.
2.0.13146.0	May 19, 2011	Reflashes the DVD drives to support XGD3 Media : PLDS DG-16D4S, PBDS VAD6038 and PLDS DG-16D2S, to a new stock firmware : 0272, 04421C, 02510C. Also patches Samsung MS25 & MS28 Anti-Piracy 2.5 scheme updated. Support for the new XGD3 disk format for games, adds 1GB of usable disk space and extra anti-piracy features to new games Adds a new 1 hour Auto-Off setting in addition to the 6 hour Auto-Off setting previously available. Adds PayPal support as a payment option for all Xbox Live users. Minor bugfix.

Please note: In order to use the SMC Hack, you must not have installed any of the 849x kernel updates.