Microsoft products usually have an end-of-support date, where no more feature updates and security patches will be offered. However, earlier this month, Microsoft has released a security update for Windows XP, an operating system that has been unsupported since 2014. Although releasing a patch for an old system seems unusual, Microsoft does have its reasons.

Both businesses and individuals across dozens of countries are scrambling to fix their computer systems after a ransomware, named WannaCry, caused major disruptions earlier this month. Like most ransomware, WannaCry encrypts files and demands a Bitcoin payment for their release.