WorldOfWar.Net relays a warning from Blizzard for World of Warcraft owners planning on installing the Wrath of the Lich King expansion for the MMORPG. It seems the expansion will ship with version 3.0.1, so if you've still got the version 3.0.2 patch on hand, you are advised not to delete it, so you can easily get back to the latest version after installing the expansion. Thanks Ant.