RH Satellite upgrade (6.3->6.4->6.5->6.6->6.7) advise

Hi all,

I did a recent job change and at the new place, there is a RH Satellite infrastructure with around 80 provisioned hosts. Everything is working and since today noone have done any patches/upgrades or whatever to any of the linux machines (both the Satellite & the hosts). The whole environment is "closed" - no connection to the Internet and that is why they had no problem going on without updates, etc.
So my job now would be to upgrade the Satellite and the hosts. With the hosts, I do not have a problem - it is pretty plain - if the developers allow certain package updates, I do it - end of story (same with security updates, etc).
With the Satellite though, it is not so easy. I have never "touched" that software, so I am trying to build a test environment currently (based on Satellite 6.3), to provision some hosts, to try some things - basically to feel the software. There are some custom puppet modules, that are build from people that are long gone from the company, but as far as I can see this is the only "special" thing about it.
Enough about the context, now about the actual question. Do you think it is really necessary to update the Satellite server? Having in mind that the environment is not connected to the Internet and all.
The RHEL hosts are 7.6 & 7.5 and because of the application, no migration to 8.* is planned for the foreseeable future. As far as I understand from RH docs, Satellite 6.3 will not have problems supporting RHEL 7.5, 7.6.
Thank you in advance.