Is it possible to "legally" upgrade Mac OS Snow Leopard to some more recent version?

Question

macOS

Good afternoon.
There is an old MAC with Snow Leopard and Windows. Under Snow Leopard almost never sat and did not update it.
Now the question arose whether it is possible to somehow update Snow Leopard (after 10 years) officially, legally.
When searching for updates, he writes:
""Software Update" cannot be checked for updates due to network errors"
There is a connection to the waffle, the pages are loaded, but slowly.
Thanks in advance for advice and tips.
ps and do not ask where the desire to revive the mammoth
comes from Best regards, Cuoca

Answer 1

As an option, you can boot into Mac recovery, where it should, in theory, pull up the latest version via wifi ...
If the Mac is so old that it still doesn’t know how to do this, make a bootable USB flash drive with the desired distro, install from it. just look at the compatibility, to which version updates were released for this poppy