Microsoft Graph vs. Exchange Online: Room Calendar Connection Options in Launcher

This article explains the two ways Launcher can connect to a Microsoft 365 room calendar — Microsoft Graph and Exchange Online (legacy) — what's different between them, the benefits of each, and what permissions you'll be asked to approve.

Overview

When you connect a room calendar in Launcher under Microsoft Calendar, you can choose from three connection types:

• Microsoft Graph — Microsoft's current, recommended integration method
• Exchange Online — the original connection method, kept available for organisations that prefer it
• Exchange Server — for on-premises Exchange deployments (unaffected by anything in this article)

This article focuses on the difference between Microsoft Graph and Exchange Online, since both connect to the same Microsoft 365 / Exchange Online mailbox — they just use a different Microsoft API and permission model to do it.

Quick comparison

Benefits of Microsoft Graph

• Microsoft's recommended approach. Graph is the integration path Microsoft is actively developing and supporting long-term, so it's the more future-proof option.
• Tighter, calendar-specific permissions. The Launcher app now requests only the permissions strictly needed to read the room calendar (see the Permissions section below) — an earlier version over-requested an unrelated file-access permission, which has since been removed.
• Consistent sign-in experience. Signing in looks and feels the same to the end user as the legacy method — there are no extra fields or steps, only (in some organisations) an extra one-time approval step handled by IT.

Benefits of Exchange Online (legacy)

• No extra admin consent step. Because this method doesn't register through the same enterprise app permission model, it generally connects without triggering a Microsoft Entra "approval required" prompt — useful if your organisation's app-approval process is slow or restrictive.
• Familiar behaviour. If your organisation connected room calendars before the Graph rollout and didn't experience any issues, this option preserves that exact behaviour with nothing to change.
• A ready fallback. If you run into a Graph consent issue you can't resolve quickly, switching to Exchange Online gets the room calendar working again without waiting on an IT approval.

Permissions requested

Both methods request delegated (user-based) access — Launcher never requires an admin to create an application-only/service-account style integration for either option.

Microsoft Graph

Microsoft Graph requests the Microsoft Graph scope needed to read events from a shared or room mailbox calendar (Calendars.Read.Shared), along with the standard sign-in permissions Microsoft applies to any app (basic profile/sign-in). An earlier release also requested a file-access permission (Files.Read) left over from an older mobile authentication flow — this was unrelated to calendar access and has been removed, so the permission prompt now only asks for what's needed to read the calendar.

Why might I see an "Approval required" message?
Some organisations configure Microsoft Entra ID to block users from consenting to new third-party app permissions on their own. If your organisation has this setting, the first person to connect a calendar via Microsoft Graph will see an approval-required prompt.

What the user sees: A message asking them to request approval, with an option to notify their IT administrator.

What the IT admin needs to do:

1. Sign in to the Microsoft Entra admin centre.
2. Go to Enterprise Applications → Admin consent requests.
3. Locate the pending request for Launcher and review the Microsoft Graph permissions being requested.
4. Approve the request. Admins can approve for a single user or grant organisation-wide consent so no one else in the organisation needs individual approval.
5. Once approved, the user returns to Launcher and reconnects their calendar — the connection completes normally.

Exchange Online (legacy)

This method authenticates with the same delegated sign-in but against the older Exchange Online endpoint rather than Microsoft Graph. It requests calendar access only and does not go through the same Microsoft Entra enterprise app consent screen, so organisations typically won't see an admin approval prompt with this option.

Which option should I use?

• Start with Microsoft Graph unless you have a specific reason not to — it's the option Microsoft is investing in going forward.
• Choose Exchange Online if your organisation's IT approval process is a blocker, if you were already using this method successfully before the Graph option existed, or if you hit a Graph-specific issue you need a quick workaround for.
• Exchange Server remains the right choice only if your mailboxes are hosted on-premises rather than in Microsoft 365 — this option isn't affected by anything above.

How to switch connection type

1. On the device, go to Settings → Room Calendar (or the equivalent screen during first-time setup).
2. If a calendar is already connected, disconnect it first.
3. Choose Microsoft Calendar, then select either Microsoft Graph or Exchange Online from the three options shown.
4. Sign in with the appropriate Microsoft 365 account and, if prompted, complete the admin approval steps above.
5. Confirm the room calendar's events appear on the Launcher display.

Note: Devices already connected via Microsoft Graph (from Launcher 2.5.1 onward) will keep using Graph after updating — you only need to actively choose a connection type if you disconnect and reconnect the calendar.

Common issues

• "Approval required" message when connecting or reconnecting — see the Microsoft Graph permissions section above; this needs a one-time approval from your IT administrator.
• Calendar events not refreshing / stuck on old meetings — this is unrelated to which connection type is used and is generally resolved by reconnecting the calendar or restarting Launcher.
• "Launch Meeting" button missing for Teams meetings booked in New Outlook — this is a known Outlook compatibility issue affecting both connection types; New Outlook doesn't currently write the Teams join link into the calendar event the same way Outlook Classic does.