Arc Sysem Works translated by Gematsu said:PlayStation 4 Owners
By downloading a free update due out on February 20, 2020, the battle balance will be updated to match Under Night In-Birth Exe:Late[cl-r].
By installing the update and purchasing various downloadable contents, you can have the same content as a new copy of Under Night In-Birth Exe:Late[cl-r].
PlayStation 3 and PS Vita Owners (currently only confirmed for Japan)
Users who own the digital version of Under Night In-Birth Exe:Late[st] for PlayStation 3 or PS Vita will be able to purchase the digital version of Under Night In-Birth Exe:Late[cl-r] for PlayStation 4 at a discounted price (from 5,280 yen to 2,000 yen) for a limited time (from February 20, 2020 to April 30).
To receive the discount, simply purchase the digital version of Under Night In-Birth Exe:Late[cl-r] for PlayStation 4 via the PlayStation Store with the same PlayStation Network account previously used to purchase the digital version of Under Night In-Birth Exe:Late[st] for PlayStation 3 or PS Vita. Confirm that the discount price is applied before purchasing.
Really happy they're doing this instead of handling it like Exe:Late to Exe:Late[st] (buy it all again, lmao). Hopefully the eventual PC port of [cl-r] will do the same thing so the playerbase isn't further split.