For some reason no buttons are showing on the suscription page once the user has logged in.
You can see it here: http://cl.ly/image/003c131i1I3N
Ive followed the instructions from here https://premium.wpmudev.org/forums/topic/membership-upgrade-buttons-not-showing, but still doesnt show up.
Did a rsearch and fount that the problem is in line 242 on includes/renew.form.php.
It seems that method_exists($gateway, 'display_upgrade_from_free_button') return false.