Response.sendFile is undefined. Existing express applications must update it to "sendfile".

[exceptDefeat]

The documentation states that express.io is a clean drop-in replacement for express. Existing express code that uses Response.sendFile(), breaks when dropping replacing express with express.io.

The behavior is reproducible when installing express.io via npm. I haven't verified whether or not it exists in master in the git repo.

[sibartlett]

You can try my fork, which uses the latest version of express and socket.io: https://github.com/sibartlett/express.oi