I am new to d3.js and I am trying to learn by changing/looking at chunks of code.

I am running into the following issue: I get a Uncaught (in promise) TypeError: d3.forceSimulation is not a function

This is the line where I am getting the error:

const simulation = d3.forceSimulation(nodes)
    // .force('charge', d3.forceManyBody().strength(5))
    .force('x', d3.forceX().x(function(d) {
        return xCenter[d.category]
    }))
    .force('y', d3.forceY().y(0))
    .force('collision', d3.forceCollide().radius(d => 1.1*d.r*Math.sqrt(2)))
  //.force('collision', collide)
    .on('tick', ticked)

I have the following d3.js version loading in my html: <script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>

If I load <script src="./../d3.v6.js"></script> nothing will render. What might be the problem here?