Review for ExQuilla for Exchange by Rick Yagodich
Rated 5 out of 5 stars
It works. It connects (once one figures out the full URL needed to talk to office365). It makes e-mail possible when a client decides they are too good to use open standards and instead insist on using a proprietary protocol.
And $10/y is a pittance considering the alternative is to use webmail, or Outlook.
To create your own collections, you must have a Mozilla Add-ons account.