Sioux Falls, SD (KELO-AM) - Microsoft is letting customers know that they should start planning for the end of technical support and security updates for its venerable XP operating system. It first shipped in 2001. Microsoft says it will retire its old, dependable operating system as of April 8. MS Windows Director Greg Sullivan, says it's an standard industry move to retire operating systems in the constantly evolving tech world. XP users are being asked to go to AmIRunningXP.com for information on how to upgrade their systems. Microsoft is encouraging its customers to upgrade to its Windows 8 operating system, which has received mixed reviews.