This patch includes a revamped PVP honor system, the new arena system, a new looking-for-group system, new talents for each class, and more. It updates World of Warcraft from from version 1.12.0 or 1.12.1 to version 2.0.1.
To apply this patch, do the following:
1. Copy the folder named "WoW-1.12.x-to-2.0.1-enU-patch" to your World of Warcraft folder.
2. (Windows) Run Updater.exe from that folder (Mac) Run Updater.app from thatfolder.
This will apply the patch to your current WoW 1.12.0 or 1.12.1 version.