[Samba] Need advice on upgrading from 4.3.11 to 4.8.3

[Taner Tas]

Hi all,

We have a Samba AD DC service running on Ubuntu 16.0.4 with Samba 4.3.11.
We are planning to upgrade it to a recent version, probably 4.8.3.

I think that I have two options:

a) Package upgrade via 3rd party repositories (Louis Van Belle's repo)
by following wiki.

b) A fresh install of 4.8.3 on another VM then join it to 4.3.11 as backup DC,
then transfer all FSMO roles on new and finally demote older one.

Since this a production environment, I have to accomplish this task transparently.
Is there anyone out there who did same task before? I'll appreciate any advice
regarding this.

Thanks.
-- 
Taner Tas