Here's the official announcement:
Microsoft provided support for Windows XP for the past 12 years. But the time came for us, along with our hardware and software partners, to invest our resources toward supporting more recent technologies so that we can continue to deliver great new experiences.
As a result, technical assistance for Windows XP is no longer available, including automatic updates that help protect your PC. Microsoft has also stopped providing Microsoft Security Essentials for download on Windows XP. (If you already have Microsoft Security Essentials installed, you will continue to receive antimalware signature updates for a limited time, but this does not mean that your PC is secure because Microsoft is no longer providing security updates to help protect your PC.)
If you continue to use Windows XP now that support has ended, your computer will still work but it might become more vulnerable to security risks and viruses. Internet Explorer 8 is also no longer supported, so if your Windows XP PC is connected to the Internet and you use Internet Explorer 8 to surf the web, you might be exposing your PC to additional threats. Also, as more software and hardware manufacturers continue to optimize for more recent versions of Windows, you can expect to encounter more apps and devices that do not work with Windows XP.
If you are still using Windows XP with Bootcamp we recommend you update to newer supported operating system. Microsoft and Best Buy are offering $100 trade-in offers for old devices running Windows XP.