A customer would like to be able to use the IRM mail encryption/security feature in Outlook 2016.
It is my understanding that since the customer and all of their user have Office 365 Business Premium licenses, they will need to purchase Azure Information Protection as an add-on.
My question is:
Do all the customers users need this add-on or do they only need one add-on/license to be able to use this feature?
I understand that at least one add-on is needed to configure the module in Azure AD, however if a user without this add-on tried to use the feature in their outlook would that work?