That said, Microsoft hasn’t released security updates for XP since early 2014, so while you’ll be able to keep playing League on Service Pack 3 you’ll still be vulnerable to risks which could compromise your League account. The only versions of Windows compatible with the latest protocols are XP Service Pack 3 and above for 32-bit, and Vista and above for 64-bit. This isn’t a change to League itself, but a required security update to the connection between players and our servers. Service Pack 2 is no longer compatible with the latest security protocols. Unsupported systems might not be able to communicate with our servers and anyone still running Service Pack 2 won’t be able to log in or play the game. If you don't have a service pack installed, you'll only see your operating system version.
If you're on a 32-bit OS, you can download and install Windows XP Service Pack 3 for free here. If you are on an operating system using Windows XP Service Pack 2, check out the steps below to avoid an interruption of service. We’re announcing the end of League of Legends' support for Windows XP Service Pack 2, effective June 1.