[2021] Update Preview: Embrace the Abyss

We always aim for backwards compatibility with existing saves. With this update however, the radiation feature will only kick in once you start a new campaign, and additionally, we are aware that old campaigns may not correctly spawn missions for abandoned outposts – this latter one is an issue which we are still hoping to fix before the update though. Aside from these two exceptions, you should not need to restart to get the new features!