I am being tasked with developing an integration with an external system and from my reading the best way would be to use the Azure Service Bus.

According to this MS article Service integration architecture with Windows Azure Service Bus Relay | Microsoft Docs it says Azure Directory Federation Services (ADFS) is needed, but is that outdated?

For e-mail approval workflows using the mobile connector, it required ADFS but now allows Azure Active Directory (AAD).

Does this only allow AIF or could I also expose the AX services? I'm very green on this so I may be saying things incorrectly.