Predator: Hunting Ground has received a free update and a DLC every month since release, and October's has just landed. The highlight is the new DLC, which introduces a Viking Predator for $4.99. This Predator has visited Earth during the Vikings era to test the most powerful Nordic warriors and picked up a few of their traits along the way.
In practical terms, the Viking is the strongest, but also the slowest predator in the game, and comes equipped with a battle axe. In terms of gameplay style, you will need to focus more on his combat skills and raw power than the actual technology.
As for the free update, it serves mostly to balance and fine-tune certain weapons, but also to motivate players to choose more varied combinations of soldiers to fight the Predator. You can check the full notes in the Official PlayStation Blog.