Department, Job (JobTitle) and Title are already handled (see NGVCard+ActiveSync.m)
Office is not included in the request sent by OL. i.e. cannot be sycned.

Supervisor (ManagerName), Assistnat (AssistantName), Partner (Spouse) and Anniversary are not yet handled.

We could do the sync like this:
ManagerName > x-(ms)-manager
AssistantName > x-(ms)-assistant
Spouse -> x-(ms)-spouse
Anniversary -> x-anniversary

I find OfficeLocation in the sogo.log if I enable EAS debug:
<OfficeLocation xmlns="Contacts:">Büro A2</OfficeLocation>

JobTitle is handled as you say, it seems OL is sending nothing:
<JobTitle xmlns="Contacts:"/>

It would be nice if you can handle the other fields as you proposed.

One question. Are this fields syncable over CalDAV?

In the meantime I have noticed that PDF files attached to an appointment are not synchronized either.
Should I create a new bug report for this issue?

Binary attachments in apointments are not supported by SOGo.
There is another feature request open for that already.

(Just my 2ct: In my opinion that is nonsense, as you bloat your calendar, which is synchronized to all sorts of devices. Instead use a cloud storage and add the link to it.)

I agree with you. But explain that to someone who has used Outlook with Microsoft Exchange for years.
I think SOGo is very good software and have been using it since 2014. But I wouldn't use it to replace Exchange servers. Please do not take this as a complaint. Many thanks.
The ticket can be closed.