<header id="page-header" class="navbar navbar-full dc-navbar-primary dc-navbar" role="banner">
  <% if @use_minimal_nav %>
    <nav class="nav navbar-nav pull-xs-right">
      <%= link_to 'DocumentCloud', '/', class: 'nav-item nav-link dc-logo' %>
    </nav>
    <nav class="nav navbar-nav pull-xs-left">
      <%= link_to "&larr; #{@minimal_back_text}".html_safe, @minimal_back_link, class: 'nav-item nav-link' %>
    </nav>
  <% else %>
    <div class="row">
      <div class="col-xs-10 col-md-3">
        <nav class="nav navbar-nav">
          <%= link_to 'DocumentCloud', '/', class: 'nav-item nav-link dc-logo' %>
        </nav>
      </div>
      <div class="col-xs-2 hidden-md-up">
        <button id="dc-main-nav-toggler" class="navbar-toggler pull-sm-right" type="button" data-toggle="collapse" data-target="#dc-main-nav">☰</button>
      </div>
      <div class="col-xs-12 col-md-9">
        <div id="dc-main-nav" class="collapse navbar-toggleable-sm">
          <nav class="nav navbar-nav pull-sm-right">
          <%= render "common/new/nav_#{'un' unless @current_account}authenticated" %>
        </nav>
        </div>
      </div>
    </div>
  <% end %>
</header>

<header id="page-header" class="navbar navbar-full dc-navbar-primary dc-navbar" role="banner">
  <% if @use_minimal_nav %>
    <nav class="nav navbar-nav float-right">
      <%= link_to 'DocumentCloud', '/', class: 'nav-item nav-link dc-logo' %>
    </nav>
    <nav class="nav navbar-nav float-left">
      <%= link_to "&larr; #{@minimal_back_text}".html_safe, @minimal_back_link, class: 'nav-item nav-link' %>
    </nav>
  <% else %>
    <div class="row">
      <div class="col-xs-10 col-md-3">
        <nav class="nav navbar-nav">
          <%= link_to 'DocumentCloud', '/', class: 'nav-item nav-link dc-logo' %>
        </nav>
      </div>
      <div class="col-xs-2 hidden-md-up">
        <button id="dc-main-nav-toggler" class="navbar-toggler float-sm-right" type="button" data-toggle="collapse" data-target="#dc-main-nav">☰</button>
      </div>
      <div class="col-xs-12 col-md-9">
        <div id="dc-main-nav" class="collapse navbar-toggleable-sm">
          <nav class="nav navbar-nav float-sm-right">
          <%= render "common/new/nav_#{'un' unless @current_account}authenticated" %>
        </nav>
        </div>
      </div>
    </div>
  <% end %>
</header>

Update markup for Bootstrap v4 alpha 5 compat
Update markup for Bootstrap v4 alpha 5 compat
