For many Office 365 administrators, the announcement last month that Unified Messaging is being retired from Exchange Online will not be any great surprise. Back in 2017 – a very long time ago in Office 365 terms – Microsoft announced the discontinuation of support for third party systems using Unified Messaging; and subsequently have removed Unified Messaging from Exchange Server 2019. The writing has been on the wall for some time.

Of course, if you are using Unified Messaging today, this might not come as welcome news.

Why is Microsoft retiring Unified Messaging?

If you consider the wider Office 365 picture, then it doesn’t make a lot of sense for Microsoft Exchange to continue to be the platform for receiving voicemail. More than ten years ago when UM was introduced with Exchange Server 2007, the world was moving into a new world of Unified Communications with voicemail being a standard service relied upon by many.

However, UM launched only months before the iPhone launched, back in 2007. The smartphone market exploded, and a lot of the functionality in UM like being able to dial-in to your mailbox and listen to messages became quickly redundant.

Over the next few years, Microsoft Office Communications Server was re-launched at Lync Server and latterly, Skype for Business Server. From Lync onwards, Microsoft made large in-roads into large enterprises and built a reputation as a formidable competitor to established telephony vendors.

However, despite the success of Exchange, many organizations using third-party phone systems didn’t make the jump to UM – even if they had it licenced, and instead preferred to use voicemail systems closely integrated with the telephony system. The only exception to this was of course Lync and Skype for Business.

Therefore, with the purpose of voicemail remaining a simple use-case for recording messages – rather than a complex dial-in access system to mailboxes – and the majority of UM users being Lync/Skype for Business users – the logical location for voicemail really wasn’t in Exchange Server.

Is UM being replaced – and what do I need to do?

Yes – Unified Messaging is being replaced, by Cloud Voicemail. Cloud Voicemail is the service organizations using Skype for Business Online, Microsoft Teams and Exchange Server 2019 use to replace Unified Messaging. In short, it’s a tried and tested service.

The good news is that for many organizations, the voicemail migration will be done for you including Microsoft performing the testing and validation on their side. However, there are many cases where you’ll need to perform some of your own actions – and you will more than likely need to inform users of changes in functionality.

What do I need to watch out for?

Although migration is largely Microsoft-driven, there are a number of areas where you will be impacted and will need to perform actions against your environment:

  • If you are running Lync Server 2010 and use Exchange Online UM you will need to upgrade to at least Lync Server 2013 – ideally though you will move to Skype for Business Server 2019 or 2019; or move to Microsoft Teams if you can.
  • If you aren’t running Skype for Business Hybrid, then you will need to enable it for your organization. This wasn’t a necessity for Unified Messaging with Exchange Online, but is for Cloud Voicemail.
  • If you are using Auto Attendants, then you will need to re-create these in Cloud Auto Attendant.
  • If you have fax integration with UM, then this won’t be available with Cloud Voicemail.

In addition, not all features available in Exchange Online UM are supported by Cloud Voicemail. These are helpfully highlighted by Microsoft, but for ease of reference, these are the key features that aren’t available today:

  • PSTN Dial-In Access
  • PSTN Outlook Voice Access
  • Using Play on Phone to record greetings
  • User settings to disable transcription
  • Voicemail broadcast features
  • Voicemail notification via SMS
  • Call answering rules (C1 CY19)
  • Play on phone to listen to the message (PSTN)
  • IRM – Protected message and Private Messages
  • Silence detection
  • Changing Recording duration from 5 minutes
  • Changing PIN failure from 3
  • Disable/Enable missed call notification
  • Auto attendant transfer to external PSTN number (Q2CY19)
  • Auto attendant dial an extension (CY19)
  • Auto attendant leave a message (CY19)

Finally, because UM was an Exchange feature and is replaced by a different technology, the interface that users access to update their voicemail settings changes. Instead of accessing the Outlook on the web options pages, users will need to access the Cloud Voicemail portal.

Over the coming months, you need to watch the Office 365 Message Center – with the first notifications already on their way for transitions in March. You can find more about the scheduling on Microsoft Docs.

If your organization has embraced the Teams revolution but adoption is slow, check out How to get your team ‘on Teams’ – a helpful guide outlining Teams best practices.

About the Author

Steve Goodman

Technology Writer and Chief Editor for AV Content at Practical 365, focused on Microsoft 365. A 12-time Microsoft MVP, author of several technology books and regular Microsoft conference speaker. Steve works at Advania in the UK as Field Chief Technology Officer, advising business and IT on the best way to get the most from Microsoft Cloud technology.


  1. Mike

    Hi –

    I have on-prem Skype for Business 2015 and Exchange 2019 hybrid connected w/ Exchange Online UM.

    I’m trying to find out if I need to acquire any licenses, such as a Phone System License, just to use Cloud Voicemail since ExoUM is going away.

    Would you happen to know?

    Thank you

    1. Michael

      Hey Mike, did you ever get your answer? I’m need to know this as well.

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