A new user cannot be created without assigning a user role to them anymore (user role setting can be found under Permissions tab). When trying to do so, you will face an error stating: "Cannot add user: field "roleid" is mandatory".
The count_foreach function now returns '0' for a matching item in the array, if no data are present for the item or the data do not match the filter. Previously such items would be ignored (no data added to the aggregation).