[Samba] Demoting offline DC on 4.3.11-Ubuntu

[Mickey Bankhead]

I have recently added a DC to my AD - Former DC was Samba 4.1.6, new DC is
4.3.11 (latest supported by Ubuntu).

There's also a Window 2008 server I had tried to join as an AD - that
server, wouldn't completely join and replicate to the 4.1.6 samba AD, and
now it will not Un-join the AD "domain" either via dcpromo.

This brings me to my actual question -

Now that I have completed all the steps to join and migrate my AD to the
new samba server, samba-tool domain demote will NOT succeed for my old
4.1.6 DC - it complains about the "broken" 2k8 AD server, and won't demote.

I thought I would  shut down the old 2k8 broken DC and the 4.1.6 DC
servers, and then demote these "offline" servers?  BUT The samba.org howto
for demoting offline servers
https://wiki.samba.org/index.php/Demoting_a_Samba_AD_DC
says if you are running older than samba 4.4, then upgrade samba first
before demoting offline servers.   -  well - I am already running the
latest Ubuntu "official" samba - 4.3.11 -- Does this mean I should NOT try
and demote until I upgrade to 4.4?

Ubuntu does not supply 4.4 yet - so I'd have to install from source - which
I hate to do on a production server because I then have to manually
maintain updates forever (instead of just running apt-get to update)...

Any thoughts/recommendations?