In a 2.8 course we set a "Grade to pass" in 5 Quiz activities.
In the 5 quizzes, we set "Require grade" in Activity completion.
This way, students could see the green flag in the completion activity box if they achieved the passing grade or the red cross if they didn't achieved it.
Setting Course completion, we selected the quizzes to be completed in "Condition: Activity completion" (and as Condition requires: ALL selected activities to be completed).
The student had the course completed only if they got the grade to pass in each quiz.

In the same course in 3.0.5, these same settings make the course completed in a different way: we found out that even if the minimum grade is not achieved in a quiz, the course is completed, since the quiz had been graded.

The only way to get the minimum grade in order to complete the course is to edit the Activity completion options in Quiz activity: unchecking the option "Require grade" and checking "Require passing grade" instead.
This solution doesn't show the red cross or the green flag in the quiz activity option box but only the blue flag at the achieving of the minimum grade.