Troubleshoot: Fix Internet Explorer 8 mess up WordPress themes

Use this service to test the pages https://netrenderer.com

https://developer.microsoft.com/en-us/microsoft-edge/

How to fix Internet Explorer 8 messing up WordPress themes

Download virtual machines
Test Microsoft Edge and versions of IE8 through IE11 using free virtual machines you download and manage locally.
https://developer.microsoft.com/en-us/microsoft-edge/tools/vms/

https://developer.microsoft.com/en-us/microsoft-edge/tools/screenshots/