[twitter-bootstrap] bootstrap 4 responsive utilities visible / hidden xs sm lg not working

Having an issue with the new responsive utilities hidden / visible classes, when migrating to Bootstrap 4. I am aware that .hidden- classes have been removed from v3 and replaced with .hidden-*-up .hidden-*-down. Using the new .hidden-*-up.hidden-*-down classes but the elements aren't changing to visible/hidden. Can't figure out why.

<div class="col hidden-xs-down">
    <span class="vcard">
        …
    </span>
</div>
<div class="col hidden-lg-down">
    <div class="hidden-sm-down">
                …
    </div>
    <div class="hidden-xs-down">
                …
    </div>
</div>

* nothing is hidden in this example, regardless of screen size (Safari, Responsive Design Mode)

Some version working

<div class="hidden-xs">Only Mobile hidden</div>
<div class="visible-xs">Only Mobile visible</div>

Bootstrap 4 (^beta) has changed the classes for responsive hiding/showing elements. See this link for correct classes to use: http://getbootstrap.com/docs/4.0/utilities/display/#hiding-elements

Screen Size Class

-

1. Hidden on all .d-none

2. Hidden only on xs .d-none .d-sm-block

3. Hidden only on sm .d-sm-none .d-md-block

4. Hidden only on md .d-md-none .d-lg-block

5. Hidden only on lg .d-lg-none .d-xl-block

6. Hidden only on xl .d-xl-none

7. Visible on all .d-block

8. Visible only on xs .d-block .d-sm-none

9. Visible only on sm .d-none .d-sm-block .d-md-none

10. Visible only on md .d-none .d-md-block .d-lg-none

11. Visible only on lg .d-none .d-lg-block .d-xl-none

12. Visible only on xl .d-none .d-xl-block

Refer this link http://getbootstrap.com/docs/4.0/utilities/display/#hiding-elements

4.5 link: https://getbootstrap.com/docs/4.5/utilities/display/#hiding-elements