For many years, Microsoft has offered technical support and security updates for multiple versions of Internet Explorer. This was largely down to enterprise users where companies had difficulty in upgrading large numbers of computers to the latest version of Internet Explorer either because of the shear amount of work involved or because some web apps would not be compatible with newer browsers. As time has gone by companies have become standardised on older versions of Internet Explorer and this has created it’s own set of problems.

Come January 12 2016, technical support and security updates will only be available for the latest version of Internet Explorer for supported operating systems. See the table below for details.
Windows Platform Supported Internet Explorer Version
Windows Vista SP2 Internet Explorer 9
Windows Server 2008 SP2 Internet Explorer 9
Windows 7 SP1 Internet Explorer 11
Windows Server 2008 R2 SP1 Internet Explorer 11
Windows 8.1 Internet Explorer 11
Windows Server 2012 Internet Explorer 10
Windows Server 2012 R2 Internet Explorer 11
Support has already been dropped for operating systems not listed above (such as Windows XP) meaning you could be under threat of security vulnerabilities and no technical support should you need it from Microsoft. 
Why the change?

There are two key reasons for the change in policy from Microsoft. 
The first, and possibly most important from an end user point of view is older browsers lack the same level of security of modern browsers. Protection against malicious software increased from 69% on Internet Explorer 8 in 2009 to over 99% on Internet Explorer 11 according to an NSS Labs report. Microsoft have already made other moves to improve security on its browser. From 12 August, Internet Explorer will start to block some out-of-date add-ons, known as ActiveX controls.
The second key reason is the tremendous benefit to developers by customers upgrading to modern browsers. Older web browsers may not support modern web standards which can make building websites a much more difficult and time consuming process. From an end user point of view, websites could be “dumbed down” by developers to suit older browsers to ensure the widest reach possible for a given site. This means you could be missing out on some of the experiences the web has to offer.
Help for commercial customers

Customers should plan for upgrading to a modern standards browser in order to benefit from additional features, performance and security but Microsoft hasn’t completely abandoned their commercial customers who rely on older versions of Internet Explorer for their web apps. 
Firstly, these changes will not come in to effect until January 2016 which provides time to get web apps up and running on modern browsers.
Secondly, Enterprise Mode for Internet explorer 11, which was released in April 2014 offers enhanced backward compatibility and enables you to run many legacy apps which could provide a cost effective solution for a company in the short term. Microsoft has announced that Enterprise Mode will be supported for the duration of the operating system lifecycle which should enable existing web apps which rely on older browsers to run on the latest version of Internet Explorer. Microsoft has vowed to continue working on Enterprise Mode to improve backwards compatibility in order to help customers stay up to date with the latest version of Internet Explorer.
More Information

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