The game got updated recently (feb 18th, something around that time), which changed the encryption keys again. They tried to make it harder to find them, but here's an article demonstrating how to circumvent the security they've put to prevent reverse-engineering: https://medium.com/@xplodwild/reverse-engineering-of-a-mobile-game-part-3-now-its-obfuscated-9c31e29c386b
This update includes the new encryption keys for the fresh new "v4" API endpoint. Can't wait for the next lootbox pay-to-win event!
It also includes the patch from @notnilc which adds Raida to the list of tournament heroes you can pick.
Enjoy!