The official Battlefield account stated in their announcement:
PS4 to PS5 upgrade?
The Battlefield 2042 Cross-Gen Bundle (digital) is our solution for gamers upgrading to Xbox Series X|S or PS5, while still being able to play on Xbox One or PS4.
The Cross-Gen Bundle edition of Battlefield 2042 is now available for pre-order. Previously, if you wanted access to the two generational editions, you had to buy the Gold edition, which costs.
Battlefield 2042 will be available on PC, PS4, PS5, XOne, and Series X|S on November 19th. Players who pre-purchased (or are EA Play subscribers) will get access to the beta beginning tomorrow at 4 a.m. On October 8th, everyone will be able to access the open beta.