 repeated cross sections in pre-treatment periods using universal base period</p></li>
</ul></div>
    <div class="section level2">
<h2 class="page-header" data-toc-text="2.1.0" id="did-210">did 2.1.0<small>2021-12-10</small><a class="anchor" aria-label="anchor" href="#did-210"></a></h2>
<ul><li><p>Code is substantially faster/more memory efficient</p></li>
<li><p>Support for <em>universal</em> base period</p></li>
<li><p>Major improvements to unit testing</p></li>
<li><p>Completely removed <code>mp.spatt</