Difference between exec_mode "cluster" and "cluster_mode"

[maarekj]

What's going wrong?

The documentation states this for enabled cluster mode:

module.exports = {
   apps: [{
     script: "api.js",
     instances: "max",
     exec_mode: "cluster"
   }]
}

But for me it doesn't work. I have errors: EADDRINUSE: address already in use

If I specify "exec_mode": "cluster_mode", it works as expected.

What is the difference between the 2, and why the exec_mode: "cluster_mode" is not documented?