Opening a calendar of an Office365 shared mailbox in IOS

For some time, I've been struggling with this, but we are using Microsoft Office365 with shared (free) mailboxes and from time to time, someone wants to have a calendar of such a shared mailbox on his iOS device.

The idea of such shared mailboxes (and why they are free) is that they do not represent real users, but that they are used for generic interaction points of an organization (internal of external). Examples of such interaction points can be "billing", "planning" or "administration".

As these shared mailboxes do not have a user id, or even a password, it is very hard to configure them on the device. There is a way to open the mail by using your own credentials (if you have the permissions on the shared mailbox) by using a backdoor and configuring the mailbox as an IMAP account. this will not get your calendar configured though...

After some searching, the solution seems to be *really* simple!

All you need to do is to:

• open your mailbox in the web version of outlook by going to https://outlook.com/ <yourdomain.com>. Make sure that you are logged in with some user that has access to the shared mailbox.
• Then open the shared mailbox by clicking on your profile picture and then on "open another mailbox". In the popup that appears, fill out the email address of the shared mailbox and then continue. If you have access, you will see another tab open up and  you will see the shared mailbox.
• go to the calendar and on the menu in the top of the screen, there is a share button.
• fill out the email address of the user that wants the calendar on his phone and choose which permissions that he/she needs.
• after that, he/she will need to accept this invite after which the "shared calendar" will appear "automagically" on the phone of the specified user...

Happy sharing!