Back to June 2012 when Microsoft announced Windows Phone 8. Microsoft promised that devices running on that platform will be supported by Microsoft for 18 months, including software updates and bug fixes. In March this year, Microsoft said that they will discontinue support for Windows Phone 8 on June 8th, 2014.
Today, Tony Mestres as Vice President of Windows Phone Partner and Channel announced on Windows Phone official blog that they have extended their support for WP8 from 18 months to 36 months. It means that the support will end on January 26th, 2016. Unfortunately, the new policy is not applied for the previous WP version. So, Windows Phone 7.8 users will get support until September 9th, 2013.
In addition, Microsoft also announced new update for Windows Phone 8 called enterprise feature pack. It brings some features focus on business like VPN, email and encryption, as well as improved device controlling.