1. Go to WP Admin -> Plugins -> Editor -> WPLMS Customizer -> customizer_class.php
2. Add the following line in _constuct function :

PHP Code:

 

add_filter('wplms_unit_mark_complete',array($this,'wplms_assignments_complete_force_unit_complete'),1,3);

 

3. Add the following function in class :

PHP Code:

 

function wplms_assignments_complete_force_unit_complete($mark_unit_html,$unit_id,$course_id){
    $flag=0;
        $unit_assignment = get_post_meta($unit_id,'vibe_assignment',true);
        if(isset($unit_assignment) && $unit_assignment){
            $user_id = get_current_user_id();
            $assignment_complete = get_post_meta($unit_assignment,$user_id,true);
            if(isset($assignment_complete) && $assignment_complete > 1){
              $flag=0;
            }else{
              $flag=1;
            }
        }
        
  if($flag)
      return '';
  return $mark_unit_html;
}

 

Change 1 to some custom value X , if you want the student to score X marks before he can mark the unit complete.