etc/config.xml
<?xml version="1.0" encoding="UTF-8"?>
<!--
/**
* config.xml
*
* @copyright Copyright © 2017 Staempfli AG. All rights reserved.
* @author juan.alonso@staempfli.com
*/
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
<default>
<staempfli_mailcatcher>
<configuration>
<enabled>0</enabled>
</configuration>
</staempfli_mailcatcher>
</default>
</config>