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IE11 compatibility#

There are some caveats if we still want to target IE11 as supported browser.

Version pinning#

These package versions should be pinned to this especific versions, unless their code or dependencies have some es6 only compatible, because their maintainers mainly target the node world.

  • "query-string": "4.1.0"
  • "superagent": "3.8.2"


Then in the project that should target it, these changes are required:

add as a dependency @babel/polyfill.

yarn add @babel/polyfill

and in src/client.jsx:

import '@babel/polyfill';


See for more updated information


Razzle supports @babel/preset-env, that supports including browserlist in package.json. So you can add this to package.json:

  "browserslist": [
    "last 2 version",
    "IE 11"

This supports the query specific DSL for browserlist targeting the browsers that you need to add.


Some packages in node_modules are ES6 only, for some older browsers, you might want to add a pre (or post) transpiling. There's a script pre-build-transpiling.js (Volto root folder) that might help you with it. Also this command line might help:

./node_modules/.bin/babel --presets="@babel/env" XXX --out-dir XXX