As was previously announced on February 26th 2016, EVE Online support for Windows XP and Windows Vista will soon come to an end.
On June 30th 2016 we will discontinue support for the old EVE launcher, which will also bring our Windows XP and Vista support to an end. Players still using Windows XP will be unable to launch the EVE client from the new EVE Launcher.
Microsoft ended the mainstream support for Windows XP 7 years ago (14 April 2009) and extended support ended 2 years ago (April 8th 2014). While we wanted to maintain support for XP and Vista for as long as possible, it is now causing too great a burden on our development team.
Although we are aware this change will affect 3.2% of our player base, we cannot continue to maintain the additional overhead supporting this platform causes. Sunsetting Windows XP support will simplify development and the complexity of our platform testing. This allows us more time to focus on new features, such as providing a smoother and more enjoyable experience on our DirectX 11 client and puts us in a better position to end DirectX 9 support in the near future.
If you are unsure what Operating system you have you can check on this site, and you can continue to discuss this announcement in this forum thread.