In China, because a large number of players do not own the computer on which they play games (e.g. if they play in Internet cafés), the CD keys required to create an account can be purchased independently of the software package. To play the game, players must also purchase prepaid game cards that can be played for 66 hours and 40 minutes. A monthly fee model is not available to players of this region. The Chinese government and NetEase, the licensee for World of Warcraft in China, have imposed a modification on Chinese versions of the game which places flesh on bare-boned skeletons and transforms dead character corpses into tidy graves. These changes were imposed by the Chinese government in an attempt to "promote a healthy and harmonious online game environment" in World of Warcraft. The Chinese government delayed the release of the Wrath of the Lich King expansion, due to what it deemed objectionable content. NetEase took over licensing of World of Warcraft from The9 in June 2009 following the expiration of The9's contract, and were able to secure a launch for Wrath of the Lich King on August 31, 2010, nearly two years after its Western release.
Blizzard makes use of a system known as Warden on the Windows version of the game to detect third-party programs, such as botting software, allowing World of Warcraft to be played unattended. There has been some controversy as to the legality of Warden. Warden uses techniques similar to anti-virus software to analyze other running software on the players' PCs, as well as the file system. However, unlike most anti-virus software, it sends a portion of this information back to Blizzard, which caused privacy advocates to accuse it of being spyware. One example of the information Warden collects is the title of every window open on the system while WoW is running. On the other hand, many gamers responded positively to the development, stating that they supported the technology if it resulted in fewer cases of cheating. Blizzard's use of Warden was stated in the Terms of Agreement (TOA).
When new content is added to the game, official system requirements may change. In version 1.12.0 the requirements for Windows were increased from requiring 256 MB to 512 MB of RAM. Official Windows 98 technical support was dropped, but the game continued to run there until version 2.2.3. Before Mists of Pandaria, World of Warcraft will officially drop support for Windows 2000.
Patch 1.9.3 added native support for Intel-powered Macs, making World of Warcraft a universal application. As a result of this, the minimum supported Mac OS X version has been changed to 10.3.9; World of Warcraft version 1.9.3 and later will not launch on older versions of Mac OS X. PowerPC architecture Macs are no longer supported since version 4.0.1.