Overwrite the Avisota 2 header and footer with static content in all templates.

dcaconfig.php

<?php

/**
 * Hint: this will overwrite the template for ALL mailings!!!
 * There is no solution yet to manipulate this in a simple way for each theme/layout.
 */

foreach ($GLOBALS['AVISOTA_MAILCHIMP_TEMPLATE']['templates'] as &$template) {
	$template['cells']['header']['content'] = '<h1>My superious newsletter: ##message.subject##</h2>';
	$template['cells']['footer']['content'] = '<p>Acme Company, Master street 123, 45677 Example town, USA</p>';
}