As noted in #350 web-vitals no longer works in IE9 as of version 2.1.2. It probably still works in IE10 and IE11 but is no longer tested in either and so is at risk of breaking in either soon.
With all versions of IE not officially unsupported I think it's best to remove any language of it's support from the README. Perhaps this should be a breaking change and saved for v4, but as noted v3 (and also the latest version of v3) already are not reflective of the actual situation so I'm tempted not to leave this for v4 and just merge this.
As noted in #350 web-vitals no longer works in IE9 as of version 2.1.2. It probably still works in IE10 and IE11 but is no longer tested in either and so is at risk of breaking in either soon.
With all versions of IE not officially unsupported I think it's best to remove any language of it's support from the README. Perhaps this should be a breaking change and saved for v4, but as noted v3 (and also the latest version of v3) already are not reflective of the actual situation so I'm tempted not to leave this for v4 and just merge this.