There’s one breaking change this release:

• send_frame/2 is now synchronous and returns an error when connection is opening or closing.

I think the most exciting thing about this release is the addition of OTP based debugging capabilities. Check it out and provide feedback!

Take a look at the v0.3.1…v0.4.0 diff, the release on hex.pm, or the v0.4.0 Release Notes for more information