Humly Control Panel in an Exchange Hybrid Environment

This article explains how Humly Control Panel (HCP) works when your organisation runs Exchange in a hybrid setup, with some mailboxes on Exchange Server on-premises and some in Exchange Online (Microsoft 365). It covers what HCP needs, what can stay where it is, and how to plan the setup.

In this article

• The short answer
• How HCP uses your Exchange environment
• What a hybrid setup needs
• Common hybrid scenarios
• Licensing
• Planning the migration
• Frequently asked questions

The short answer

Humly supports Exchange hybrid environments. HCP works with the resource mailboxes of your rooms and desks, not with the mailboxes of your users. The resource mailboxes that Humly manages must be in Exchange Online. User mailboxes can stay on Exchange Server on-premises, be in Exchange Online, or be a mix of both. No user migration is required for Humly to work. HCP is connected to Microsoft 365 as its booking system and uses the Microsoft Graph API both for the resource calendars and for looking up users in Microsoft Entra ID, wherever their mailboxes are.

How HCP uses your Exchange environment

In a hybrid environment HCP is always connected to Microsoft 365 as the booking system and communicates with your tenant through the Microsoft Graph API. The Graph API gives HCP access to the resource calendars in Exchange Online and to the user directory in Microsoft Entra ID, which covers both cloud users and users whose mailboxes are still on-premises.

With the Microsoft 365 integration, HCP does three things:

• Reads and writes resource calendars. Every booking, check-in, extension, early release and cancellation is read from or written to the calendar of the room or desk mailbox. HCP also subscribes to changes in these calendars so the room display updates in real time.
• Looks up users in the directory. When a user books from a Humly Room Display with an RFID card or PIN, or signs in to a Humly app, HCP looks the user up in Microsoft Entra ID (Azure AD) by email address or user principal name. HCP never opens the user's own mailbox.
• Sends notifications. Emails such as booking confirmations are sent from the sender mailbox configured in Global Settings. See What is sender email in Global Settings?

Because HCP only touches resource calendars and the directory, it does not matter where a user's mailbox is. On-premises users are synchronised to Entra ID by Microsoft Entra Connect as part of every hybrid deployment, so HCP finds them in the same way as cloud users.

What a hybrid setup needs

On the Humly side:

• The room and desk resource mailboxes that Humly manages are hosted in Exchange Online.
• HCP is connected to Microsoft 365. Follow Booking System Preparation - M365 and Connect HCP to Microsoft 365.
• The sender mailbox used for notifications is in Exchange Online.
• Any security groups used for Humly sign-in or RFID enrolment exist in Entra ID, either created there or synchronised from on-premises Active Directory.

On the Microsoft side, a standard hybrid deployment already provides what Humly relies on:

• Directory synchronisation with Microsoft Entra Connect, so on-premises users and groups exist in Entra ID.
• Hybrid mail flow between Exchange Server and Exchange Online, so a meeting invitation from an on-premises user reaches a cloud resource mailbox.
• Free/busy sharing between on-premises and online, so users see room availability in Outlook regardless of where the room mailbox is.
• Automatic booking enabled on the resource mailboxes, so Exchange accepts or declines invitations without a delegate. See Microsoft Calendar Processing for Humly Administrators.

Common hybrid scenarios

Resource mailboxes in Exchange Online, users on-premises or mixed
This is the supported hybrid setup. Connect HCP to Microsoft 365 by following Booking System Preparation - M365 and Connect HCP to Microsoft 365. An on-premises user books a room in Outlook as usual. The invitation travels over hybrid mail flow to the cloud room mailbox, Exchange Online accepts it, and HCP shows the booking on the room display. The organiser's name is shown correctly because HCP resolves it from Entra ID.

Resource mailboxes still on-premises
Migrate them to Exchange Online before connecting HCP. HCP reads resource calendars through the Graph API, which only reaches mailboxes hosted in Exchange Online. The move is a standard hybrid mailbox migration and does not affect your users. After the move, confirm automatic booking is enabled on each mailbox as described in Microsoft Calendar Processing for Humly Administrators, then connect HCP to Microsoft 365 as above.

Resource mailboxes split between on-premises and Exchange Online
Only the rooms whose mailboxes are in Exchange Online can be managed by Humly. Rooms whose mailboxes remain on-premises are not visible to HCP until they are migrated. Move all resource mailboxes that Humly will manage to Exchange Online.

Already running HCP against Exchange Server, now migrating resources to Microsoft 365
This is a common situation. A single HCP installation connects to one booking system, so it cannot read some rooms from Exchange Server and others from Exchange Online while the migration is under way. The recommended approach is a staged migration with two HCP installations running side by side:

1. Set up a second HCP connected to Microsoft 365. Humly can provide a cloud-hosted HCP for this, or you can install another HCP on your own server with the Microsoft 365 backend. Contact support@humly.com to arrange the option that suits you and the licenses for the transition period.
2. Migrate resource mailboxes to Exchange Online in batches that fit your rollout plan, for example one building or floor at a time.
3. After each batch, add the migrated rooms to the new HCP and move their room displays and booking devices over. The rooms that are still on-premises keep working on the existing HCP.
4. When the last resource mailbox has moved, decommission the Exchange Server HCP.

Users are not affected by the staging. They keep booking in Outlook as before, and each room is served by whichever HCP its mailbox currently belongs to.

Licensing

Room and equipment mailboxes in Exchange Online are free. Microsoft does not require a license for a resource mailbox unless it needs features beyond the standard 50 GB mailbox, such as an archive or litigation hold, which Humly does not use. Migrating resource mailboxes to the cloud therefore does not increase your Microsoft 365 licensing.

Humly licensing is unchanged by a hybrid setup. Licenses are per room display, booking device or feature, exactly as in a fully on-premises or fully cloud environment.

Planning the migration

1. List the rooms and desks Humly will manage and confirm each has a resource mailbox.
2. Migrate those resource mailboxes to Exchange Online with a standard hybrid mailbox move. Keep the on-premises object as a remote mailbox so hybrid mail flow and free/busy keep working.
3. Verify automatic booking is enabled on the migrated mailboxes, as described in Microsoft Calendar Processing for Humly Administrators.
4. Prepare the Microsoft 365 tenant for HCP and connect HCP to Microsoft 365, following the guides linked above.
5. Test with an on-premises user and a cloud user: book a room in Outlook, confirm it appears on the display with the correct organiser, then book and check in from the display and confirm it appears in Outlook.

If HCP is already in use against your on-premises Exchange Server, follow the staged migration described under Common hybrid scenarios instead of switching the existing installation, so rooms stay on their displays throughout the move.

Frequently asked questions

Do our users have to be migrated to Microsoft 365 before we deploy Humly?
No. Only the resource mailboxes need to be in Exchange Online.

Can on-premises users book rooms from the Humly Room Display with RFID or PIN?
Yes. HCP looks the user up in Entra ID, where synchronised on-premises users exist. The booking is created in the cloud room mailbox and the user is added as organiser.

Will on-premises users receive Humly email notifications?
Yes. Notifications are sent from a cloud sender mailbox and delivered to on-premises recipients over hybrid mail flow.

Can we keep some rooms on-premises and move the rest?
Not for rooms managed by Humly. All Humly-managed resource mailboxes must be in Exchange Online. Rooms that Humly does not manage can stay wherever you like.

We already use HCP with Exchange Server. Can we just switch it to Microsoft 365 once the rooms have moved?
Only if every Humly-managed resource mailbox moves at the same time, which is rarely practical. For a gradual move, run a second HCP with the Microsoft 365 backend and transfer rooms to it as their mailboxes migrate. See the staged migration scenario above.

Does Humly need access to user mailboxes?
No. HCP's permissions are limited to the resource mailboxes and read access to the directory. See Azure Application Access Policies for how to restrict HCP to the resource mailboxes only.

We use Humly Visitor with the Outlook add-in. Does hybrid affect it?
The add-in itself works for all users. Deployment differs: Centralized Deployment from the Microsoft 365 admin center reaches Exchange Online mailboxes, while on-premises mailboxes receive the add-in through the on-premises Exchange admin center.

If you have questions about your specific hybrid environment, contact support@humly.com.