The last version of Internet Explorer, version 11, was released on October 17, 2013. This is a very long time ago when taking into account the rapid development of web technologies. These days it is often difficult and time consuming to get modern technologies to work well in this old browser. More and more frameworks are dropping support, and even Microsoft themselves has announced that they will fully drop support for IE in their own services in 2021.
Consequently, we have decided to not include support for IE in the Design Library website.
The error line on input fields has been decreased to 2 px.
The error indicator for input fields have a 2 px line (#D81A1A) at the bottom.
The reasoning for changing the line from 4 px to 2 px is that the line was too hefty, especially when there were many fields lighting up at the same time.
We try this for now and evaluate. Please give us feedback so we can learn in time for the next update.