In web, login as admin in a 3.4+ site, go to Calendar and create: 1 category event, 1 course event and 1 activity event (e.g. chat activity). In the app, login in that site with a user that is enrolled to the course that has the event and activity and that's also enrolled to 1 course that belongs to the activity that has the event. Go to calendar. Check that you can see the 3 events. Open the activity event. Check that you see a button to go to the activity. Click it and check that the activity is opened. Open the activity event again. Check that you can click the course and it's opened. Now open the course event. Check that the course is clickable too. Now open the category event. Check that you can click the category name and the category is opened. In web, login as admin in a 3.3- site, go to Calendar and create 1 course event and 1 activity event (e.g. chat activity). Repeat steps 2-6 with this site except point 4 (the button to open the activity isn't displayed in sites previous to 3.4).