According to Edvin Ryding's (Wilhelm) Twitter, he improvised the football field scene.
According to Edvin Ryding (Wilhelm) Twitter, the scene where him and Ivar Forsling (Erik) run away and fall down was an accident. Edvin didn't have traction on his shoes and fell, accidentally bringing Ivar down. Ivar ended up bruising his hand.
The first scene to be filmed was the scene where Wilhelm and Erik run away and fall down. The actor, Edvin Ryding, stated this on his Twitter.
Christian Hillborg, known from The Last Kingdom (2015) and Fleabag (2016), makes a short guest appearance as August's stepdad.
The boarding school "Hillerska" does not exist in real life. Filming location was primarily at Kaggeholms Slott on Helgön (just outside Ekerö island) very close to Stockholm.