materio-base-d7/sites/all/modules/contrib/admin/footer_message/footer_message.install

<?php

/**
 * Implements hook_enable().
 * Provides an upgrade path from Drupal 6.x sites to Drupal 7.x,
 * checking to see if the site_footer variable has been set for a D6 site,
 * if so - grab that value and pass to our new footer variable.
 */
function footer_message_enable() {
	$old_footer = variable_get('site_footer', FALSE);
	$new_footer = variable_get('footer_message_msg', FALSE);
	if (($new_footer == FALSE) && $old_footer) {
		variable_set('footer_message_msg', array('value' => $old_footer));
	}
}