thank you very much for your reply. Great, that gives me hope that it is possible.;) Based of that link you've posted I found inspiration again and did a bit of further research (matching Outlook 2016). I found that MS provides a set of Group Policies to chance the contact card details. I also played a little bit with that. But, unfortunately the replacements doesn't work.
I used the values and filled it with the specific values:
thank you so much for your effort!! Okay, that's truly a proof. Obviously I'm doing something wrong.
I configured both registry keys as well, but the changes wont take effect. In this case I used the label telephone "work" to override and linked it with the AD-Attribute "employeeID".
The result (after gpudpate & Outlook restart).
I don't have a glue what I'm doing wrong. My guess - is there a specific way how to link the AD-Attribute? The attribute is configured in both sources (AD and Azure AD) with same ID and filled with Information.
As already said, I'm really grateful for your help!
I would like to thank you! The MAPI values are working well. I was hoping that the AD-Attributes are also working, therefore I've opened Ticket at Microsoft Support. Our findings are the same - the MAPI values are the only working solution to rewrite information in the outlook contact card.