Microsoft 365
The planning stays in elektro.box, the calendar stays Outlook. Whoever is assigned sees the appointment where they look anyway — and the planning sees when they are already busy.

In elektro.box
Every appointment somebody is assigned to appears in their Outlook calendar, and changes follow. The other way, elektro.box reads only when somebody is busy — never the titles of other entries.
For the whole business, IT consents once; after that it applies to every person. If you only want to connect your own calendar, you do that under «My account».
Data flow
From elektro.box to Microsoft 365
From Microsoft 365 to elektro.box
Setup
Choose the tile
Under Settings › Integrations, choose «Microsoft 365». For the whole business, this is reserved for the owner account.
Consent
An administrator of your Microsoft account consents once. Microsoft calls this «Read and write calendars in all mailboxes»; your IT can restrict it in Exchange.
Assign
From then on every appointment lands in the Outlook of the person assigned.
What it does not do
What is connected is the calendar, not the mailbox: elektro.box does not read Outlook mail. Without Microsoft 365, you subscribe to your appointments as a calendar link in Outlook, Apple or Google.
45 minutes, at your place or on screen. We go through your programs and tell you what can be connected and what stays as it is.