extra/Templates for bootstrap 4/extcal/extcal_navbar.tpl
<ul class="nav nav-tabs">
<{foreach item=navItem from=$tNavBar}>
<li class="nav-item"><a href="<{$navItem.href}>" class="nav-link<{if $navItem.current|default:false}> active<{/if}>"><{$navItem.name}></a>
</li>
<{/foreach}>
</ul>