Hi,
So the issue is that the document is not getting loaded, not that WebViewer isn’t getting loaded (I can clearly see that WebViewer is loaded in the IE11 screeshot). Please make sure to be more specific in your issues!
We do thoroughly test PDF.js Express in IE11 before every major release, so I am quite confident that everything should work as expected. Can you make sure that your code is reaching your loadDocument call? I see that you are loading a Blob from S3, can you make sure that all that code is getting run properly?
Thanks,
Logan