By default, a case tile will display the message count and timeline, calculated on the basis of unread messages from all sources in the last 24 hours.
It's possible to change the view of all cases, by opening the 'View' option, at the top of the case overview. Here you can make a selection that best suits your interest.
This selection will only apply to yourself. By using the 'Reset' option, you go back to the default view. Please note that it's only possible to select and view a maximum of 4 months.