We had issues being continuously logged out when our admin IP changes which we solved on a 5.7 site with the following settings in application/config/concrete.php:
<?php
return array(
'security' => array(
'session' => array(
'invalidate_on_ip_mismatch' => false,
)
)
);

Does anyone know how to do this for a site in 5.6.3.5? We aren't upgrading it to 5.7/5.8 at the moment as it's using eCommerce.

I had a look through concrete/config/app.php but couldn't find any settings relating to the session IP.

Any help appreciated!