https://www.pcgamer.com/all-dauntless-accounts-will-be-converted-into-epic-games-store-accounts-soon/

Dauntless, the multiplayer behemoth basher, will be ditching its launcher soon and converting all player accounts into Epic accounts. Announced at the Game Awards, the free to play game will launch on the Epic Games Store and adopt a Fortnite-style structure, but that does mean beta players will need to download the store client before Dauntless’ launcher vanishes. Developer Phoenix Labs has posted an FAQ that covers the migration. 

You don’t need to do anything at the moment, so you can keep using the old launcher. Eventually, however, that’s going to be flung in the bin. There’s no date yet, but in the weeks approaching the switch, Phoenix Labs will start to convert accounts, at which point you’ll have to use the Epic Games Store.