Breaking changes

• Dropped support for Node.js < 4.5.0 (#1313).
• The connection is no longer closed if the server does not agree to any of
  the client's requested subprotocols (#1312).
• net.Socket errors are no longer re-emitted (a4050db).

Features

• Read backpressure is now properly handled when permessage-deflate is enabled
  (#1302).