code> callback. This gives applications more control over handling server responses.</li>
<li>hyperscript: when attributes have a <code>null</code> or <code>undefined</code> value, they are treated as if they were absent. <a href="https://github.com/MithrilJS/mithril.js/issues/1773">#1773</a> (<a href="https://github.com/MithrilJS/mithril.js/pull/2174">#2174</a>)</li>
<li>API: <code>m.request</code> errors no longer copy response fields to the error, but instead assign the parsed JSON response to <code>erro