[PS4] Upgrading mutations

Can someone explain to me how to upgrade the mutations? I read on the homepage, that with “Seed of Evil” it will be possible to upgrade some of them, but I don’t find any option for this. Does it only work when playing the expansion ((after the main campaign))? Or do I have to start a whole new game so the expansion can work properly?
Thanks!

Hello @Santiago, you’re only able to upgrade your mutations during the DLC, so after you finish the main campaign and transition into the DLC or if you start playing on the DLC.