Spacing Utility Classes
Bootstrap 5 changes some common utility classes to help with responsive design. Instead of l or r for left or right, Bootstrap 5 uses s or e for start and end. For instance, if you used ml or mr to set margin spacing you need to change that to ms-* and me-*.
Documentation: https://getbootstrap.com/docs/5.0/utilities/spacing/
Because this is a result of moving from Bootstrap 4 to 5, if you make this change before August 3, it is recommended that you avoid publishing the page before August 3.