Basic Express/Node Function Syntax Not Working

On my Mac, I can create a simple "Hello World" Node/Express app like this:

const express = require('express')
const app = express()

app.get('/', function(req, res){
  res.send('Yo')
})

app.listen(3000, () => 
  console.log('Listening on port 3000...')
)

It works great. But when I install my Node app on my web host (DreamHost), I make sure I'm on the same version of Node and NPM, and I do npm install and then restart the server.

Passenger complains about the syntax:

/home/labrumco/progressbox.net/app.js:9
app.listen(3000, () => 
                  ^
SyntaxError: Unexpected token )

Why would it reject that syntax? My guess is some kind of syntax dependency, but I'm too new to Node to know the difference. :)

If I change it to this it works:

app.listen(3000, function() {
  console.log('Listening on port 3000...')
})

function(){ works instead of () =>

Why is this happening?

--- Update ---

Here is my package.json file:

{
  "name": "...",
  "version": "1.0.0",
  "description": "...",
  "main": "app.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Clifton Labrum",
  "license": "ISC",
  "dependencies": {
    "express": "^4.16.3",
    "node-fetch": "^2.2.0",
    "nodemon": "^1.18.3",
    "request": "^2.88.0"
  },
  "repository": {
    "type": "git",
    "url": "..."
  }
}