This update can be applied to any WoW installation that has already been patched to 3.0.2. As the game is supported in many regions, be sure to download the correct one for your region. Also, be sure to avoid applying this patch until the servers for your region have also been updated to 3.0.3.
I am honestly not sure what to do after installing this file. It gave me a Zip file, which after I unzipped gave me a WoW-18.104.22.16856-to-22.214.171.12483-enGB-patch.app folder. That one's contents were two folders MacOS, Resources, and two files Info and PckInfo. I tried moving the folder to the Updates section in the WoW folder, but then everytime I started the game it downloaded the patch and gave me an error saying I already have that patch installed. It's like that everytime. Any comments?