One of the things you can and should do before moving to Windows 10 is to deploy Internet Explorer 11 on your existing machines. But if you think that means you are safe in terms of then moving to Microsoft Edge and be running with all the latest and greatest of web standard, you’d better think again. Why?
Well ever since Internet Explorer 8 the setting “Display intranet sites in Compatibility View” has been enabled. Really what that means is that although you have moved to IE11 the chances are very likely that all your LOB web apps and all intranet based sites have been running in IE7 mode the last 10 years or so, at least after moving to IE8. That’s not very good to be honest.
The solution to really be future-safe is to make sure to unset that setting to actually run all your sites in IE11 mode. This can of course be done using Group Policies by setting the policy “Turn on the Internet Explorer 7 Standard Mode” policy. However when doing that expect things to break so I strongly advise you do some thorough testing Before deploying that setting to your entire organization.