try to run a ftp server on it (without buying commercial app)
I'll admit that I was annoyed when I found out that a machine upgraded to High Sierra no longer had an ftp server. The thing is, ftp is so insecure that it has been replaced by newer, better protocols. Unfortunately, I have something that uses ftp to copy data to a remote server, and that server was one of my Macs. But as Cerebus notes, it's simple enough to install the ftp server software from homebrew, which is what i did.
try to scan from an "old" multifunction network scanner to it
Blame the manufacturer of that scanner for not keeping drivers updated, not Apple.
lets talk about the security failures of the root account that has since been corrected but ?
Yes, that was a particularly dumb error, but once it was reported, it was immediately fixed.
lets talk about the admin password that is mandatory now, and what happens when you migrate an old system that does not have a password
?
macOS is Unix; admin (root) passwords have been required since the first version of OS X.
[quote[lets talk about filevault that crypt the entire volume and external volumes without the user knowing it ?[/quote]
That's disabled by default, it does not get turned on without user intervention and admin access, and the System Preferences page for it is very explicit about the need for the user to remember a login password to use the disk. (As of High Sierra, it also gives you the option of generating a recovery key so you can decrypt the disk.)
lets talk about installing it in a mixed network environment ?
Sure, let's, as the MacBook Pro I am typing this on right now is on a network running a Windows Domain server, and I can access Windows shares on the network with my domain login. And I can access the Mac's disk from the Windows 7 machine on my desk just using my Mac user login.
lets talk about launching own apple technicians utility apps that does not detect a 10.13 to check for a bad video card ?
I've never had a bad video card, so I cannot comment.
lets talk about connecting some hdmi projectors to a 10.13 iMac that cuts the display in half (and work perfectly on the same hardware and 10.12) ?
My wife regularly connects her MacBook Pro running 10.13 to all sorts of projectors, over HDMI and DVI, and has not mentioned that problem. Perhaps you have to spend 30 seconds in the Displays System Preference after connecting the projector to ensure everything is set up?
Oh, and by the way, my wife tells me that at every conference she attends, there is always someone with a Windows laptop who simply can't get their machines to talk to projector. It's always a problem.
Any more?