If you're still using Windows 7, you may be a bit miffed to find out that mainstream support just ended on January 13th. Extended support will still be active until 2020, but if you want major updates, you'll have to update to a new OS. Windows 8.1 is pretty solid in my opinion and with Windows 10 coming soon, I think you'll be ok. Still, it's something to take note of - there will be no more new features and enhancements, but security will continue to be updated.
Support ends 24 months after the next service pack releases or at the end of the product's support lifecycle, whichever comes first. For more information, please see the service pack policy here.
Source: Microsoft Support