[Samba] Upgrade old infrastructure running 4.3 (and 4.13)

[Lorenzo Milesi]

Hi. 
I've a hybrid installation with a master DC running Ubuntu 16.04's "stock" 4.3 Samba, and a second DC running 4.13. Currently FSMO roles are on the 4.3 as it was the first server, and I cannot transfer them to the 4.13 as there are schema differences [1].
We're finally going to upgrade unmantained Ubuntu and Samba.
>From what I could understand by reading the upgrade guides I'm going to: 
* upgrade the OS, which will take Samba to 4.7
* run db check
* install 4.14
* run db check

Is this correct or should I take other steps?

Thanks


[1] ERROR: Failed to add role 'domaindns': LDAP error 16 LDAP_NO_SUCH_ATTRIBUTE -  <attribute 'fSMORoleOwner': no matching attribute value while deleting attribute on 'CN=Infrastructure,DC=DomainDnsZones,DC=contoso,DC=lan'> <>
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Lorenzo Milesi - lorenzo.milesi at yetopen.com 
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