Is there a way to show older content in the Activity Stream widget?

I have a group on my site where we're using the Forum application to share updates. The last update that was posted was on November 3, but the Activity Stream on the group's home page is not showing anything as it seems it's too old (since it showed previously).

Is there a way to show older updates? I don't see a configuration option for it on the widget, and I don't see anything in the widget's code, in the Forum Thread Activity Story option in Widget Studio, or Admin>Activity Stream defining an end date. Is there a defined time when it "drops off" somewhere, or other places to look? 

If anyone want's to see it, here's the group: (at the bottom of the page, there's an "Updates From the Team" header) and here's the forum post in question: