[Info!] Since patch 4.2 the MPQ patches update the game from any version to the version of the patch you're installing. But if, for whatever reason, you want to install a patch released prior to 4.2, you need to install all the patches one by one.
Installing .MPQ patches
1. Download the patch you need. (MPQ patches are stored in the Updates folder and have a name similar to this: 'wow-0-15595-Win-final.MPQ')
2. Copy the file to your World of Warcraft folder. (You can save the file there when downloading)
3. Rename the file to wow-patch.MPQ
4. Run Blizzard Updater.exe - Blizzard Updater.app if you're on a Mac
(Right click and Run as administrator in Win7 or Vista)
If you have any questions please visit our Community Forum.