Any business that is part Linux and part windows, exchange infrastructure, will need an exchange client for all their Linux client machines?

Assuming web based won’t cut it for those users, then it would seem Hiri is a good fit for that business?

I can’t see in what way you are competing or displacing Outlook if you are makinhg a product for Linux. The reason it’s a viable product would be 1) because there is no Linux outlook, and 2) because a business has users that have to run Linux while others run Outlook on windows, against the same Exchange infrastructure?