bootstrap 4.0 ml-auto vs bootstrap 5 code example

Example 1: bootstrap 4 center div

<div class="d-flex justify-content-start">...</div>
<div class="d-flex justify-content-end">...</div>
<div class="d-flex justify-content-center">...</div>
<div class="d-flex justify-content-between">...</div>
<div class="d-flex justify-content-around">...</div>

Example 2: mb-0

<p class="mb-4">Lorem ipsum</p>