Check the supported OpenStack distributions here and follow their deployment guides to install or upgrade to the latest version of T4O.
Follow below steps to enable Migration Tab on Horizon.
Login to horizon container.
set DISABLED = False
in following panel files.
These files can be found at <openstack_dashboard_installed_package_path>/enabled/
Example: /usr/share/openstack-dashboard/openstack_dashboard/local/enabled/
for RHOSP17.1
Restart horizon container.