Yes. We have migrated all existing data to the new portal and you can use your existing credentials to access all your integrations, profiles and applications on the new user portal.
For WhatsApp users, only the One API integration accounts will be able to see their setups in the new portal. All legacy WhatsApp API users will have to switch back to the 'Classic view' of the portal to access their configurations. We are currently working on also migrating these integrations.