How to port Microsoft Phone System phone numbers between Office 365 Tenants?

In this post I describe and share my experience on how you can port numbers from Microsoft Phone System from one Office 365 source tenant to another Office 365 target tenant. First of all, why should you do this? Well, there are several reasons you might have to port existing phone numbers from a source to a target Office 365 tenant, e.g.

  • company merger and acquisition
  • company segregation
  • other forms of organizational restructure measures and needs
  • technology change requirements (migrate / cutover / move (partially) from a PoC environment to a production environment …)
  • security change requirements

When do you have to port phone numbers?

On the one hand, if one of the above reasons or another reason may apply to your organization. And of course, on the other hand, if your organization and you like to keep the phone numbers to carry on getting calls on these ones. To sum it up,

  • you’ll have to port phone numbers if you rely on Microsoft Phone System Calling Plans and
  • Microsoft is also your PSTN service provider from whom you get your PSTN phone numbers
  • and you might published (to suppliers, customers, partners) and adopted  these phone numbers in your company communication with the outside world … (mail signatures, business cards, …)

Is this difficult to do?

Fortunately it is not.
Still, you have to pay attention to a few things to make the phone number porting a smooth cutover and a success. I recommend to read carefully what’s on the Microsoft Phone System documentation and a blog (see links below). I do not mention here that an Office 365 Tenant-to-Tenant migration might has other challenges you have to cope with. I recommend that you plan it – the whole migration – thoroughly to get it working with a minimal impact to your users.

What numbers can I port?

You can port user and service numbers.

What do I have to do?

As a prerequisite I recommend to set up the destination tenant with the appropriate licenses (e.g. E5 + Calling Plan International + Communication Credits + Audioconf …) to be ready for assignment as soon as the numbers are available in the destination tenant. Don’t forget about setting up Communication Credits.

Besides of all your other Office 365 Tenant-to-Tenant (T2T) migration tasks as your first step please read the blog post from “Porting Cloud PSTN Telephone Numbers Between Office 365“.

What data do I need to submit to the Microsoft PSTN Porting team?

Because it is almost always the same data you need to submit to Microsoft  for a T2T migration I just created an easy to use table which you can copy and  help as a guiding and supporting tool.

DataValue (you need to insert)
O365 source tenant domain name…
O365 source tenant unique identifier
O365 source tenant (porting) PIN
O365 destination tenant domain name …
O365 destination tenant unique identifier
O365 numbers emergency location address (for the numbers) e.g. (Floor, Building,) Street, City, ZIP, Country
Number(s) to be ported from source to destination tenant e.g. +49711xxxxxxx to +49711xxxxxyy
Number type (user vs. service phone numbers?) e.g User
Requested date and time range of port requestion execution e.g. 17/03/2019 10am
Request mail-to [Microsoft PSTN Team, see port request Microsoft page] e.g. Microsoft PSTN Europe Team

What’s next?

After you have submitted the request the Microsoft PSTN Team answers, either with additional questions or a confirmation request. You than need to confirm the port request which enables the Microsoft PSTN Team to port your numbers based on the details of the confirmation mail.

During the porting

  • the numbers will be removed on the source tenant,
  • users will not be able to be called or make a (PSTN) call [inform your users early enough],
  • numbers will show up in the destination tenant.

If you have licenses, numbers ready, congratulations you made it and can now assign the user/service numbers within the target O365 tenant.

Conclusion, opinion and summary

In my opinion porting phone numbers is really a smooth migration part of an Office 365 T2T migration. Recently, I had to port numbers and was really positively surprised how straightforward and smooth it worked. The only thing I really want to note and highlight is that if you should have all your licenses early enough in the destination tenant because in a recent T2T migration the licenses where added/booked quite late and that’s why it took some time till phone numbers could be assigned to users.

Additional Ressources


Phone Number Porting Tenant-2-Tenant


Online Audiocodes Command-Line Reference Guide for SBCs/GWs Version 7.20

This post is about news regarding the Audiocodes CLI Reference Guide. If you configure Audiocodes Session Border Controllers (SBCs) or Gateways you may know that there are some features and settings you might need or prefer to set them via command line (SSH/telnet).

In the past you downloaded the latest reference guide from the Audiocodes Library as PDF. Now there is a new site where all the commands can be found and looked up. You can find the guides as before via the Audiocodes Library.

Conclusion, opinion and summary

I prefer to use the site instead of the PDFs because the commands are easier to find at least for one version. However, it would be nice to have the option to switch between versions. E.g. if you have still a SBC with 7.0 a version selection which enables you to switch from 7.20 reference guide to 7.0 would be nice. Otherwise you had to navigate via the Library to that version. Finally, this new content delivery is nice and all you need. I like it.

Additional resources

Microsoft Teams Calling for everyone

Microsoft rolls out Teams Calling for everyone. What does it imply?

It means that everybody will get the “Call”/”Phone” button in the Teams navigation pane on the left. Additionally users will get voicemail capabilities. For existing “calling” users there won’t be a change as it reads on the official roadmap.

So, your existing CsTeamsCallingPolicy etc. should be as is.

Conclusion, opinion and summary

I like this because it will make adding telephony, PSTN voice, just a tiny little change if you go for telephony with Teams. User adoption for telephony might not require so much efforts because for the user it’s just a little extra.

Additional resources

Microsoft Teams Devices and IP Phones

In this post I’d like to highlight and share resources about Teams devices and IP Phones. Does one of the following questions or even both apply to you?

  • Are you planning to transition your conference rooms to collaborative spaces and rooms? 
  • Are you planning to migrate telephony completely or partially to Microsoft Teams?

In both cases, to begin planning, I recommend to browser to and do not miss to check the below links. Microsoft as well as third-party vendors offer a wide range of devices to cover your needs by leveraging the Microsoft Teams platform. The best place to go and check for (certified) devices is the “Microsoft Teams Devices Marketplace”. There you’ll find … 

  • Headsets 
  • Speaker phones 
  • Desk phones 
  • Room systems 
  • Conference phones and 
  • Cameras 

Conclusion, opinion and summary

I recommend to take a look on the linked pages to get an overview on available certified devices.  

If you are about to start your journey towards Microsoft Teams it might help you assess your users/rooms /spaces requirements and to create suited personas (e.g. 6-Seat-Room –> Surface Hub, Office Information Worker –> Notebook + wired Headset, Assistant –> Notebook + Mobile + Teams IP Phone xyz).

Additional Ressources 

Exchange Online Unified Messaging is transitioned to Cloud Voicemail

In this post I’d like to point out the most important aspects of the discontinuation of Exchange Online Unified Messaging (hereinafter: EXO UM, voicemail and auto attendant capabilities). EXO UM is discontinued as announced by Microsoft months ago. Now, Microsoft published an information regarding the planned transition towards Cloud Voicemail. Below a short summary of the announced information by Microsoft:

  • EXO UM will be transitioned and migrated to Cloud Voicemail in calendar year 2019 (not later than February 2020)
  • Voicemail messages can still be stored on Exchange Online as well as Exchange Server
  • You’ll receive a transition notification by Microsoft via Office 365 Admin Center
  • You can postpone the transition to Cloud Voicemail via the support panel in the Office 365 Admin Center (however before February 2020)
  • EXO UM with Lync Server 2010 will not be supported anymore and will not be transitioned
  • EXO UM with Lync Server 2013 will be transitioned to Cloud Voicemail
  • EXO UM with Lync Server 2015 will be transitioned to Cloud Voicemail
  • EXO UM Auto Attendants must migrated to Cloud Auto Attendant services
  • EXO UM Auto Attendants must be re-created on the Cloud Auto Attendant service

Conclusion, opinion and summary

EXO UM will be replaced by Cloud Voicemail. The EXO UM service will be transitioned to Cloud Voicemail based on Azure. To me it seems that it will not be a big difference for your users. They’ll still get voicemail and auto attendant capabilities. It’s more an slight cut over to a different backend for the same features.

However, if you are still on Lync Server 2010 you should consider to upgrade to Skype for Business Server to carry on providing voice mail and attendant services.

In case of many auto attendant services on EXO UM you should prepare and plan to re-create auto attendant services on Cloud Voicemail.

Further Resources

My Microsoft Teams Federation Notes

In this post I’ll describe how federation towards federated partners can work. I’ll not describe meetings and guest access for Teams which are great capabilities for modern teamwork across companies but not subject for this post. Teams provides options for federation with external organisations like suppliers, clients and partners.

Basically there are eight federation scenarios I’d like to describe below. The federation scenarios are based on Microsoft Teams as well as Skype for Business.

Skype for Business Federation

Let’s take a look on federation with Skype for Business. In Microsoft Skype for Business Server / Online (hereinafter: SFBx) there are two major federation types:

  • open federation: Users can communicate openly to everyone except users behind blocked domains.
  • closed federation: Users can communicate only to federated domains configured by the SFBx admin.

Teams Federation

Now, with Microsoft Teams federation is similair to SFBx federation but not 1:1 alike.

You can decide to federate with everyone, openly, except towards blocked domains (blacklist).

Or you can decide to federate only with allowed domains (whitelist).

Another thing to keep in mind is what’s your current Teams upgrade mode or status?

In Microsoft Docs there are five modes listed but not all are available by now.

  • Islands: All workloads on SFBx + Teams
  • Skype for Business-only: SFB for all workloads. Single client.
  • Teams-only: Teams for all workloads. Single client.
  • (not in Admin Center, Feb. 2019, TAP customers-only) Skype for Business with Teams (collaboration-only): SFB for chat, calling and meetings. Teams for collaboration.
  • (not in Admin Center, Feb. 2019, TAP customers-only) Skype for Business with Teams (collaboration and meetings-only): SFB for chat and calling, Teams for meetings and collaboration.

Scenario 1a+1b

You are on Microsoft Teams.

You can federate with other organisations having a) SFBx or b) Microsoft Teams, too.

Scenario 2a+2b

You are still on SFBx.

You can federate with other organisations having a) SFBx or b) Microsoft Teams, too.

Scenario 3a+3b

You are on SFBx as well as Microsoft Teams but your Teams Upgrade mode is “Islands”.

Your users are having two clients installed and only the SFBx works for federation communication.

You can federate only via SFBx with other organisations having a) SFBx or b) Microsoft Teams, too.

Scenario 3c+3d

You are on SFBx as well as Microsoft Teams but your Teams Upgrade mode is “Islands”.

Your users are having two clients installed and only the SFBx works for federation communication.

Your users cannot have an internal cross-client chat or else c) from SFB to Teams or d) from Teams to SFB.

Drawn via Microsoft Whiteboard App by Erik

Conclusion and summary

Teams federation provides the ability to federate with external organisations similair to what we’ve used to from SfBx. Nevertheless we need to pay attention to the user experience and federation experience which migh be slightly different during a coexistence of SFBx and Teams.

Further Ressources

Manage your Office 365 ProPlus deployment with cloud-based policies (preview)

Typically you manage your Microsoft Office installations by using group policies(-only) and options you have before you deploy the software to the computers within your organisation. However, now cloud-based policies for Office 365 ProPlus are in preview (Feb. 2019). These new option helps you to centrally mange Office 365 ProPlus deployments either for domain-joined or non-domain joined (but MDM managed) devices.

The cloud-based policies are for enforced user-based settings management and can complement group policies.

It only works for the Offce 365 ProPlus suite.

Further Ressources