https://screenrant.com/office-show-michael-holly-kids-dinner-party-worse/

The Office's Michael revealed a sad detail about his relationship with Jan, a detail made worse when it was revealed that he and Holly had children.

In the finale, I recall it being revealed that Michael and Holly had children but I have no recollection of it being said that they have four kids like this article states. I have no memory of a number of children being revealed.