Some, but not all, Bootstrap classes seem to be available

Is there any reason why not all of the Bootstrap 4 classes are present in the latest Tutor release? For example:

The mt-0 class adds margin-top:0 to the element with that class
But col-sm-8 does not add the appropriate CSS styles to a element with that class

One of the basic example from the Bootstrap 4 documentation does not yield the expected column structure:

<div class="container">
  <div class="row">
    <div class="col-sm-8">col-sm-8</div>
    <div class="col-sm-4">col-sm-4</div>
  </div>
  <div class="row">
    <div class="col-sm">col-sm</div>
    <div class="col-sm">col-sm</div>
    <div class="col-sm">col-sm</div>
  </div>
</div>