[2022] Why is this game still in unreal engine 4?

I genuinely want to know, I am actually new to this game only starting to play it this week however I do have this burning question as to why this particular game is still in Unreal 4 especially since epic is publishing the game, wouldn't they be asking the devs to use the latest so that they can do more?

Again! I am just a noob and maybe my question is a silly question but after having some interesting hours on this game and realising the friend request screen looks very old compared to the newer epic games like fortnite and fall guys, I immediately went to research and found that the game is in fact running on Unreal 4. This is not being asked to be snarky or anything. I understand development can be tough as I am in Games Dev myself however I am very curious as to why the game hasn't made any jumps to a new engine. Especially one of the newer engines owned by the publisher.

I am a new player though so take my question kindly and don't be mad. please. I know not everything is about being up to date graphically I just had this question on my mind is all.