It actually depends on what kind of user base you have and the kind of content you're working with.
For government/legal content, legacy browser support is a must, so you'd have to support the older versions of IE as well. And if you have a user base that is using IE, then it's not a good idea to ignore it.
However, beginning January 12, 2016 Microsoft has officially dropped support for most IE versions(support.microsoft.com/en-us/lifecycle#gp/Microsoft-Internet-Explorer) and is encouraging the users to move to Microsoft Edge so it actually wouldn't be a bad idea to ignore IE provided the content and the audience is of the right kind.
Here's another good discussion on the same topic: hashnode.com/post/why-do-big-companies-and-clients-insist-on-ie8-support-ciibz8fja01c1j3xt87n86ed8
Hope it helps! 🙂
Mev-Rael
Executive Product Leader & Mentor for High-End Influencers and Brands @ mevrael.com