> 2) in the model creation there is a new "Model key" element. Do not know yet what is for.
It is a system-wide unique key that is used to reference the model.
4) no change in the form definition. smiley I am missing for example the "create tab" function….
Not sure what you mean? In a user task, you can set one in the 'referenced form'
> 4) in the Identity management missing two tab: only the Personal tab is there. How can I define new users or groups then?
You need to be an admin user. Did you upgrade from a previous version?
If you start with a clean db, it'll add a new admin user, that can create users and groups.
The user and groups have gotten a big overhaul and are now based on the ACT_ID_USER/GROUP tables.