Version 8.1.1 needs IE11 support

Which product are you using?
PDF.js Express Plus

PDF.js Express Plus version 8.1.1

This is printed to the developer console when you load pdfjs express

[WebViewer] UI version: 8.1.0, Core version: 8.1.1, Build: MTAvMjEvMjAyMXw2OGY2MTQ1NWU=, WebViewer Server: false, Full API: false

“ReferenceError: ‘Proxy’ is undefined
at ea (
at na (
at Ia (
at a (
at Anonymous function (
at Anonymous function (
at r (”

Detailed description of issue
I have upgraded from 7.3.1 to 8.1.1 and it breaks in IE 11. The previous version was working in IE11 and I see the development notes stating that 8.x is IE 11 compatible.

Expected behaviour
I expect 8.x to work with IE 11.

Does your issue happen with every document, or just one?
Every document

Link to document
The documents are proprietary, so I can’t share.

Code snippet

“dependencies”: {
@pdftron/pdfjs-express”: “^8.1.1”,
@vue/cli-plugin-babel”: “^4.1.1”,
@vue/cli-plugin-eslint”: “^4.1.1”,
@vue/cli-service”: “^4.3.1”,
“axios”: “^0.21.1”,
“babel-eslint”: “^10.0.3”,
“core-js”: “^3.4.8”,
“eslint”: “^6.7.2”,
“eslint-plugin-vue”: “^6.2.2”,
“vue”: “^2.6.10”,
“vue-axios”: “^3.2.4”,
“vue-tag-manager”: “^0.1.2”,
“vue-template-compiler”: “^2.6.10”
“browserslist”: {
“production”: [
“ie 11”
“development”: [
“ie 11”

Hello, I’m Ron, an automated tech support bot :robot:

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Hey there,

We have dropped support for IE11 as of version 8.0 - it was removed from our browser support page.

This should have been communicated in the change-log - this slipped my mind and I apologize for the inconvenience. I will make sure to get that updated.