Coffee Stain published an announcement of Satisfactory - Core Values Expansion with links to the Steam and Epic Games Store pages.
Announcement and availability for purchase or launch must be checked separately. Before changing your existing factory, make a backup of your world and find out if the base game needs to be updated. Whether you're playing with mods or on a dedicated server, compatibility is important for everyone involved. Don't consider having a store page a promise of the same release date on every platform.