Microsoft has now officially said the SP3 version of XP will come out of the “first half of 2008”, but some RTM (Release to Manufacturing) builds are expected to come out on the second half of April.
As well, released by Neowin, its release schedule sees April 14 as the day when support is available for the release version.
April 21 will see only OEM, Volume License, Connect and MSDN and TechNet Subscribers getting the update. Other users can receive it at April 29, where it will be up on Microsoft/Windows Update and the Download Center. However, it won’t make Automatic Update status until June 10.
SP3 contains all the previously-released XP features; meaning that you can install SP3 without installing SP1 or SP2. It will also add NAP (Network Access Protection), which allows it to take advantage of the new features on Server 2008.
It is unclear if there will be a SP4, since Microsoft said it will stop selling XP to most manufacturers and system builders on June 30, but it has extended the life of XP Home until June 2010 for budget laptops.