OK, found the answer to this one; have to edit the file that returns "author" to indicate which should be used.

The best practice would be to edit your skin and not (never) the core. It makes upgrades easier.

I have exactly the same problem. I just upgraded from 4.X to 5.1.2 and the names next to posts have been replaced by the nicknames of the authors. In old version there was a choise how to display the name (Nickname OR First - Surname OR Surname - First name). I cannot find it anymore :/

Did you removed this option or it is hidden somewhere i cannot see ?

Yes @lazikas,

That option is not available anymore ( since a long time ago now ). It will be replaced by a global setting to enable "Friendly names" mode in the whole site.

As @fplanque said, you can decide what to display by overriding the preferredname appearances in your skins.

@mgsolipa wrote earlier:

Yes @lazikas,

That option is not available anymore ( since a long time ago now ). It will be replaced by a global setting to enable "Friendly names" mode in the whole site.

As @fplanque said, you can decide what to display by overriding the preferredname appearances in your skins.

Thank you very much for your answer! It is obvious that i had not upgraded my site for a long time :)
I prefer not to change anything in skins and wait for the replacement :)

Thanks again !

It would be a nice idea to make a difference between the names in the frontend and the names in the backend. I have disabled some widgets like "last comments" because I will not show my nick in the frontend.

To overwrite it in the skin is uncomfortable and with the next update I risk to forget it.