Although Apple released an update to its Macintosh operating system this week to combat serious security flaws, Snow Leopard was not included in the update. This is the first time that Version 10.6 of its computer operating system has been left out and signals an end to updates for the 4.5 year old OS despite the fact that up to 19% of Mac computers still run it. Users of Snow Leopard are strongly encouraged to update to a version that is being updated as it leaves them vulnerable to security flaws. Microsoft will also abandon an older version of its operating system, Windows XP, in April but in this case notice was given to its clients months in advance. It is estimated that approximately 30% of PC’s still run the 12 year old XP operating system.