Microsoft, which transitioned to its new browser Edge several years ago, is now advising enterprise users to avoid its legacy browser, Internet Explorer (IE). Microsoft Worldwide Lead for Application Compatibility Chris Jackson said this week that IE isn’t really a browser but a “compatibility solution” to deal with legacy sites. Microsoft no longer supports IE with new web standards, which is at the core of the problem.

In a new blog post, Jackson said that, for some organizations, using Internet Explorer as the default for all situations “is the ‘easy button,’ because, well, most of your sites were designed for Internet Explorer, so…just…always use it, ok?” Jackson said this sort of thinking “seems like a deliberate decision to take on some ‘technical debt,’” as he put it.

He said that as the IE standards mode supported more and more standards, “we decided not to just update the mode we called standards mode, because, when we did, we risked breaking applications written for an older interpretation of the standards. So, with Internet Explorer 8, we added IE8 standards, but also kept IE7 standards.”

“That meant, for sites in the internet zone, it would default to IE8 standards, but, for sites in the local intranet [emphasis added] zone, it would default to IE7 standards.”

Jackson said companies’ “habit” of paying for extended support for legacy software “needs to stop in the case of IE.” He suggests using IE only selectively for internal sites that require it, pointing to tools that help customers make the transition and limit the use of IE to only where it’s needed.

“Internet Explorer is a compatibility solution,” Jackson concluded. “We’re not supporting new web standards for it and, while many sites work fine, developers by and large just aren’t testing for Internet Explorer these days.”