The new and completely updated website and user interface for AirwaySim is some weeks away now. There's still a lot of work to be done, but already now testing is underway for compatibility with different systems and browsers.
At this time AWS is announcing the drop of support for Internet Explorer 7 browsers (and earlier versions). We dropped support for older IE6 a year and a half ago, and today we're dropping IE7 also as it has only a very marginal share of users (0.7% globally according to W3C), and because the new layout does not fully support this ancient (released in 2006) client anymore.
The site will continue to open with old browsers like IE7 and IE6 but it displays a warning at the front page that the browser is not compatible anymore, suggesting to upgrade. Most of the content in the new layout will work with IE7 but it will have display issues in many places (content not showing, or it is misplaced etc) so its usage cannot be recommended at all anymore.
Compatibility for the new layout will be tested with IE8, IE9, latest versions of Firefox and Chrome and also on iPad (mobile Safari). Most of the new user interface and website are standard web code (with modern features, like HTML5/CSS3) so it should work on any standard-compliant modern browser.