"Windows 7 RTM (with no service pack) will no longer be supported as of April 9th, 2013, following the standard Windows support lifecycle specifying that support ends 24 months after the release of a new service pack. Rest assured that Windows 7 will continue to be fully supported for a long time, with mainstream support continuing until January 13, 2015, and extended support continuing until January 14, 2020," As Microsoft stated in a blog post
Windows 7 SP1 will continue to receive mainstream support until 01/13/2015 and extended support (paid security updates) until 01/14/2020.
Take a look at the chart below;
Source Official Windows Blog
Via Winbeta
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