Microsoft released patches for the vulnerable operating systems that can prevent the present version of WannaCry from infecting patched computers. The first patch that protects against attacks like this was released in March, though not every user automatically downloads and installs all patches or software updates. Microsoft reactively released a patch for Windows XP, a 16-year-old operating system that is no longer officially supported, yet still used in many computers. (Microsoft also released patches for two other operating systems still only in "customer support," Windows 8, and Windows Server 2003). In customer guidance released about the attack, Microsoft recommends automatically updating as a proactive measure.