Yes, now it is released and you'll get it at: http://www.asp.net/downloads/3.5-sp1/ Interesting point regarding some old posts of mine e.g Potential solution for "Validation of viewstate MAC failed" http://aspadvice.com/blogs/joteke/archive/2007/08/14/Potential-solution-for-_2200_Validation-of-viewstate-MAC-failed_2200_.aspx