Google Drops Support for Internet Explorer 9 (2013-11-11)
Google attempts to be browser agnostic in all of its standard Apps offerings so that all browsers, Chrome, Internet Explorer and Firefox, on Windows and MocOS, work equally well1. In order to make this task manageable for these other browsers, Google limits the supported versions of those browsers to the current version and the next one previous2.
Since Microsoft recently announced the release of IE 11, Google formally dropped support for IE 9 as of November 5, 2013. This does not mean that your IE 9 browser will suddenly stop functioning when you access Google Apps for Education, but it does mean that there is no testing for any new services that might be released.
Starting in the next few weeks, if you access Google Apps from an IE 9 browser you will receive a notice that the browser is no longer supported, along with advice on getting a newer version.
Google's announcement on the Google Apps Blog.
1. There are Chrome specific plugins from Google and third parties which allow the Google browser to integrate more closely with the Google services, but these are not a part of the core browser, which is written to W3C specifications.
2. For Chrome, Google only supports one browser level from each of the two channels: Stable and Beta. This is because Chrome automatically updates itself in the background as soon as there is a new image available.