With Bootstrap 4 .hidden-* classes were completely removed (yes, they were replaced by hidden-*-* but those classes are also gone from v4 alphas).
Starting with v4-beta, you can combine .d-*-none and .d-*-block classes to achieve the same result.
visible-* was removed as well; instead of using explicit .visible-* classes, make the element visible by not hiding it (again, use combinations of .d-none .d-md-block). Here is the working example:
<div class="col d-none d-sm-block">
<span class="vcard">
…
</span>
</div>
<div class="col d-none d-xl-block">
<div class="d-none d-md-block">
…
</div>
<div class="d-none d-sm-block">
…
</div>
</div>
class="hidden-xs" becomes class="d-none d-sm-block" (or d-none d-sm-inline-block) ...
<span class="d-none d-sm-inline">hidden-xs</span>
<span class="d-none d-sm-inline-block">hidden-xs</span>
An example of Bootstrap 4 responsive utilities:
<div class="d-none d-sm-block"> hidden-xs
<div class="d-none d-md-block"> visible-md and up (hidden-sm and down)
<div class="d-none d-lg-block"> visible-lg and up (hidden-md and down)
<div class="d-none d-xl-block"> visible-xl </div>
</div>
</div>
</div>
<div class="d-sm-none"> eXtra Small <576px </div>
<div class="d-none d-sm-block d-md-none d-lg-none d-xl-none"> SMall =576px </div>
<div class="d-none d-md-block d-lg-none d-xl-none"> MeDium =768px </div>
<div class="d-none d-lg-block d-xl-none"> LarGe =992px </div>
<div class="d-none d-xl-block"> eXtra Large =1200px </div>
<div class="d-xl-none"> hidden-xl (visible-lg and down)
<div class="d-lg-none d-xl-none"> visible-md and down (hidden-lg and up)
<div class="d-md-none d-lg-none d-xl-none"> visible-sm and down (or hidden-md and up)
<div class="d-sm-none"> visible-xs </div>
</div>
</div>
</div>