First posted to MSDN on Aug, 11 2014

It’s been a busy couple of months in the world of app compat, so I’ve got a backlog of things to cover. Let’s start with an FAQ that I’ve gotten in nearly every conversation I’ve had about web app compat since April. On April 8, we introduced a feature called Enterprise Mode. This is a feature designed specifically to help customers who are on Windows 7 but still using the oldest version of IE available on that platform (IE8). http://blogs.msdn.com/b/ie/archive/2014/04/02/stay-up-to-date-with-enterprise-mode-for-internet... The engineering work behind this was really a thing of beauty. Yes, it seems an obvious feature now, but a year ago it wasn’t even an idea. In fact, a year ago, I was on a plane to Japan to start the initial visits to try and figure out what we needed to build to make things easier, because we knew they were too hard. Then, we had a “One Microsoft” symphony to produce software. Consulting and Support came together with Marketing and Engineering to represent everyone’s feedback, to run a rapid beta program, and to deliver a product in just a few months. This truly is a feature designed by and for the enterprise, with a 360 degree perspective on web app compat. Easily the most collaborate project I’ve worked on at Microsoft, and if this is indicative of what we can expect in the new Microsoft, we’re in for a lot of goodness. What emerged is a high-fidelity emulation of IE8 – better than anything we’ve done before. Now, specifically, our goal wasn’t to make the emulation one that couldn’t be defeated. Rather, it was to make emulation that worked on enterprise apps that actually already existed in the wild. So, for folks who try to foil it and come up with something that breaks it, you an absolutely succeed (and I can definitely show you a few ways). But, here’s the thing – we chose not to care about potential bugs (unless they had a demonstrable likelihood of existing) but on actual bugs that exist in the real world. And the outcome of the beta is that we achieved that, but it also indicated that we were likely to run across more actual bugs, and we’re prepared for that. After that long intro, here’s the part that people are getting hung up on… Enterprise Mode does NOT replace Compatibility View. That bears repeating – Enterprise Mode does not replace Compatibility View. They seem really similar, and plenty of folks call Compatibility View “Compatibility Mode” so they sound even more similar. But they’re actually additive. As emulation of IE8, we have to include everything that IE8 had in it. And IE8 is the version that first introduced Compatibility View. So, if Enterprise Mode didn’t contain Compatibility View, it wouldn’t be a high fidelity emulator! http://blogs.msdn.com/b/ie/archive/2008/08/27/introducing-compatibility-view.aspx So, when in Enterprise Mode, you may have to fiddle around with Compat View also! Given that, here is the approach that I normally recommend when it comes to quickly testing and assessing web app compat for a migration to IE11:

  1. Just trying running it on IE11 to see if it works – there’s a reasonable chance that it will
  2. If it doesn’t work on IE11 natively, try enabling Enterprise Mode
  3. If it doesn’t work in Enterprise Mode, try modifying the Compatibility View setting (to the opposite of what it currently is)
If none of those work, you can assign it to a technical team for exploration of other document modes or configurations before diving into the code and troubleshooting, but most customers find that this clears away nearly everything, so that if there is anything that requires special attention it’s not surrounded by noise and the ambiguity that a long list of “I don’t know” apps brings.

Another conversation this normally leads into is “wow, Enterprise Mode is way easier and more powerful to manage using group policies than Compat View was, do the changes apply to compat view also?” The good news is that we didn’t make things any worse – it’s just as manageable as it has been since IE8. The bad news is that we didn’t make things any better (and the question implies that it’s not good enough, as do the inevitable sighs). But we’ve definitely heard the feedback that this is an experience folks would like to see improved!