Undefined mixin 'media-breakpoint-only'
<p>I am trying to start some bootstrap4/sass coding.</p>

<p>I thought I did everything required to configure my environment/project setup:</p>

<p>using</p>

<blockquote>
  <p>ruby 2.3.1p112 (2016-04-26 revision 54768) [i386-mingw32]</p>
</blockquote>

<p>amongst installed gems (tried some bootstrap 3 before):</p>

<blockquote>
  <p>autoprefixer-rails (6.3.6.2)<br>
  bootstrap (4.0.0.alpha4, 4.0.0.alpha3)<br>
  bootstrap-sass (3.3.7, 3.3.6)<br>
  breakpoint (2.7.0)<br>
  compass (1.0.3)<br>
  compass-core (1.0.3)<br>
  compass-import-once (1.0.5)<br>
  sass (3.4.22)<br>
  sass-globbing (1.1.5, 1.1.0.pre.0)<br>
  sassy-buttons (0.2.6)<br>
  sassy-maps (0.4.0)<br></p>
</blockquote>

<p>in styles.scss:</p>

<blockquote>
  <p>@import "compass/css3";<br>
  @import 'variables/<em>.</em>';<br>
  @import "bootstrap";<br></p>
</blockquote>

<p>in config.rb:</p>

<blockquote>
  <p>require 'compass/import-once/activate'<br>
  require 'bootstrap'<br>
  require 'sass-globbing'<br>
  require 'breakpoint'<br></p>
</blockquote>

<p>but my compass is working and producing styles.css:</p>

<pre><code>/* line 18, c:/Ruby23/lib/ruby/gems/2.3.0/gems/bootstrap-4.0.0.alpha4/assets
/stylesheets/bootstrap/_normalize.scss */
body {
  margin: 0;
}
</code></pre>

<p>only untill some bootstrap mixins are used:</p>

<pre><code>Error: Undefined mixin 'media-breakpoint-only'.
</code></pre>

<p>What am I missing?</p>