Microsoft Office Outlook users have an out of the box tool for keeping track of their tasks, but also of tasks assigned to others.
The ability to assign tasks is dependent on Outlook and e-mail server’s capacity to accept and transmit RTF formatted (TNEF) e-mail messages.
It DOES NOT require Exchange Server.
So if you want to allow users to assign tasks between different servers / domains, all you have to do is add exceptions on the mail server or service so that e-mails are not converted from RTF.
Assigning tasks should work between:
– Exchange on premises <-> Exchange on premises
– Exchange on premises <-> Exchange Online (Office 365)
Let me know if you need help setting the exceptions and I’ll add details on this post.