Foundation uses newer CSS techniques and Jquery which require newer browsers to run on. Users on Chrome and Firefox are generally automatically updated by default, so these users are rarely on old versions. However, Internet Explorer 9 or above is required for Foundation.

Because there are still a number of users stuck on older versions of Internet Explorer, we have built in support to deliver a non-responsive version of the site to them.

To create a non-responsive version of your skin for users on IE8 and earlier, it should be called the same as your main skin, but with 'NonResponsive' added to the name. For example, we ship Kartris with a default skin called 'Kartris', and the non-responsive version of this is therefore called 'KartrisNonResponsive'.

If you're upgrading a site to the responsive version of Kartris, you could keep your old skin and rename it to be used as the non-responsive skin.

From January 2016, Microsoft will only support the latest version of its browser available on each platform, which effectively means IE8 is no longer supported (as Vista can run IE9). From this date, the requirement to service older browsers should cease as they are no longer supported with security fixes, and every browser vendor will be delivering regular browser updates automatically by default.