It is generally good IT practice to keep up to date on browser versions. Older versions of Internet Explorer are no longer officially supported by Microsoft. As of Jan 2016, only the most recent version of IE supported by the operating system will be supported. Users are encouraged to ensure they are on the most recent version of operating system and internet explorer.
Any vulnerabilities found in older version of internet explorer will not be patched by Microsoft and could therefore potentially leave the underlying system vulnerable to exploitation.
* (Current - 1) or Current denotes that we support the current stable version of the browser and the version that preceded it. For example, if the current version of a browser is 24.x, we support the 24.x and 23.x versions.