End of support for Exchange Online Unified Messaging (UM) voicemail in conjunction with third-party PBXs.

On July 20, 2017, Microsoft announced the end of support for Exchange Online Unified Messaging (UM) voicemail in conjunction with third-party PBXs.  This impacts customers with a TDM or IP PBX that is connected to Office 365 via a Session Border ControllerIf you use Exchange voicemail with a box from Audiocodes, Sonus, or Dialogic, this impacts you.  Skype for Business Enterprise Voice customers are not impacted, nor are users of third party vmail systems that deposit vmails into Exchange Online.

What’s behind this announcement?  As customers retell it, in the Summer of 2016, there were nagging issues with the head-end Session Border Controllers in the Office 365 data centers.  These are the SIP firewalls that interface the customers’ SBCs mentioned above.  The issues caused customer outages and burned manhours.  Microsoft must have perceived more customer risk in continuing the service than in discontinuing it.  As an aside, Microsoft has been making progress with their Cloud PBX service, and rebuilt a voicemail platform on Azure to support Skype for Business Cloud PBX users.  Having this additional service capability natively in Office 365 added fuel to the fire to discontinue the integration with third party PBXs. 

Microsoft announced four options to move forward, outlined below with some comments.  From their blog Discontinuation of support for Session Border Controllers in Exchange Online Unified Messaging:


Targeted Customers

Option 1: Complete migration from 3rd party on-premises PBX to Office 365 Cloud PBX.

This works for organizations already using Skype on-premises or Cloud PBX for dial tone, and who were moving from legacy PBX to Cloud PBX.  They’ll simply need to move more quickly.

Option 2: Complete migration from 3rd party on-premises PBX to Skype for Business Server Enterprise Voice on-premises.

This option works for organizations who’d already had Skype voice on-premises for dial tone, and who had planned to migrate from legacy PBX to Skype for dial tone.  Again, quickly.

Option 3: For customers with a mixed deployment of 3rd party PBX and Skype for Business, connect the PBX to Skype for Business Server using a connector from a Microsoft partner, and continue using Exchange Online UM through that connector. For example, Audiocodes UX  can be used for that purpose.

This is the most complicated option, and with the longest set of pros/cons (outlined below). 

Option 4: For customers with no Skype for Business Server deployment or for whom the solutions above are not appropriate, implement a 3rd party voicemail system.

Sure, organizations who want to keep their PBX can install a voicemail system like AVST’s Call Xpress.  Such systems can deposit messages in Exchange Online, provide Message Waiting Indicators on PBX phones, and synchronize the read/unread voicemail messages in Outlook with the phone’s blinking light.

There is cost and effort in setting up a new system (which in the case of AVST, could be in the cloud), and retiring the Session Border Controllers.  It also requires reprogramming any AutoAttendants that were set up on Exchange UM Online, as well as training users. 


Option 3 has its unique set of Pros/Cons.  Prior to elaborating, here’s a bit of context. 

With this option, Skype for Business is the connector between a customer PBX on premises and the Office 365 data center.  For Microsoft, this eliminates the need for the SBCs in the Office 365 data centers, simplifies support, and makes the service more consistent overall.  Long-term, with end of life of the third-party SBCs imminent, this should in fact make for a more stable service for customers who remain on Exchange UM.  

But it does require Skype for Business, on premises.  SfB Server can communicate with Office 365 in two ways: natively through the Skype Edge Server, or through an innovative SBC/Skype combo box from Audiocodes or as MSFT mentioned in the blog, TE Systems. 



The current Exchange UM Voicemail service remains the same.  This option won’t impact the use of Exchange UM for users AutoAttendants, or compliance.  Customers with large Auto-Attendants or who archive and use Exchange Archiving or manage voicemails with Rights Management Services won’t have to change vmail configs.

To connect to Exchange Online, requires either implementing Skype for Business Enterprise Voice or a combination of an SBC with Skype voice capabilities built in. 



The user experience remains the same.


Additional licensing cost in the SBC/Skype device, and in additional Skype voice licenses.  Plus CALs or a subset of the Office 365 E5 license will be needed to connect SfB to Exchange UM Online.  This is overpaying for voicemail, but Enabling Technologies is under advisement from Microsoft that some pricing flexibility exists.  The positioning from MSFT is that since the cost is the same, moving to SfB voice would provide more services for the same money. 

Some investments in existing SBCs may be leveraged.

Users wouldn’t necessarily need to change PBX phones, Skype just acts as a passthrough for voicemail from the on-premises PBX to Exchange Online.

You can weigh in on a public forum if you’re impacted.  Or feel free to contact Enabling for more information and to discuss your options.  Enabling Technologies is an AVST reseller and a Skype and Office 365 integrator, and is at your service to talk through your options. 




Work with our team of Cloud Computing Consultants who have done this so many times they know all of the “minefields” to prevent missteps.