I believe it actually supports IE9+ but the tests are currently failing so they ...

kasbah on Aug 12, 2017 | parent | context | favorite | on: Immutable Data Structures That Are Compatible with...

I believe it actually supports IE9+ but the tests are currently failing so they are marked red in the test array. I suspect that they are only failing for the development branch and everything works with IE9+ if you use the latest release.