Confusing mismatch, release notes vs. documentation, browser support

[bazineta]

In the release notes, there's this:

We are now making heavy use of ES2015 features, this means we have dropped out-of-the-box support for Node 4 and earlier, and many old versions of browsers. (#1541, #1553)

In contrast, in the documentation:

In the Browser Async should work in any ES5 environment (IE9 and above).

Given the statement in the release notes, the documentation is surprising; I'd think there'd be no ability to support IE at all.

Which is correct?

[aearly]

Ah, the former. It won't work out of the box in any version of IE (at least not without transpiling).