The Mail module is also webmail and mobile client. It has a business value, cause it’s possible to relate and convert an email in an another business module. It’s multi-accounts and IMAP. It’s everytime possible to “talk” about an email internally at your team avoiding any forwarding.
Invoice
The Invoices module contains all the information to create and send to the customers invoices based on selled products and services.
Project task
The Project task module is related to the Project Plan module and it manages all the different operations related to a Project.