Skype for Business Server SE — Microsoft 365 Local
To leave Skype for Business or stay there, but be supported.
For business telephony, the solution today is Teams Phone, and we’ve been managing these migrations for ten years. But not all organizations can make the switch: when data must remain on-premises, Skype for Business Server it’s now available in a Subscription Edition, and Microsoft has made it the voice component of Microsoft 365 Local, running on Azure Local infrastructure.
Skype for Business Server The 2015 and 2019 versions have been out of support since October 14, 2025, as have the 2016 and 2019 client versions. No more security patches, no more bug fixes, and no more support. And unlike Exchange, there is no paid extension period: the only two supported options are the Teams or the Subscription Edition.
The Dates That Matter
A server that's no longer supported is still making noise. That's exactly the problem.
A Skype for Business 2019 version that is out of support handles calls exactly the same way it did the day before. It simply no longer receives security patches, fixes, or support—and no one notices until an incident occurs. Here is the actual timeline, as published by Microsoft.
July1, 2025
Skype for Business Server SE is coming
The subscription version is available. It follows a modern lifecycle: no more one-time purchases of specific versions, and no announced expiration date as long as it is kept up to date.
October 14, 2025
End of support in 2015 and 2019
Both server versions are reaching end of support, along with the 2016 and 2019 client versions. No more security updates, no more fixes, and no more Microsoft support.
Since then
No paid deferral
Whereas Exchange Skype for Business , unlike [the other service], which has benefited from an extended period of security updates, does not. A server left in 2019 is vulnerable, with no option to extend its service period.
At least 2,035
Microsoft's Commitment
Microsoft has committed to supporting the subscription editions ofExchange, SharePoint and Skype for Business at least through 2035. That’s what makes an on-premises project a viable option.
Two paths remain open, and a third combines them: Teams Phone, Skype for Business Server SE —either on its own or as part of Microsoft 365 Local —or both coexisting. We assess the existing environment and tell you which one fits your constraints, even when the answer isn’t what we’d like.
See Skype for Business Server SEThe Starting Point
What project are you working on?
Five situations, five methods, five timelines. The first question isn't "which product?"—it's where you're starting from, where you're going, and what's keeping you there.
Skype for Business to Teams Phone
This is by far the most common approach, and the one we recommend when there are no obstacles to it. We have implemented it for up to 8,000 users across 39 countries.
Our Microsoft Page Teams2019 to Subscription Edition
The upgrade is performed on-site, like a cumulative update, provided that the prerequisites have been met. The server remains the same, and users are not affected.
The section Skype for Business Server SE2015 or earlier
There’s no direct path: a new farm is needed, followed by the relocation of users and the dismantling of the old one. At that cost, the question of Teams comes up again in earnest.
Microsoft 365 Local, for Sovereignty
Exchange, SharePoint and Skype for Business run on a local “Azure ” infrastructure that you own, either online or completely offline. This is the project that’s bringing this page back into the spotlight.
The section Microsoft 365 LocalTeams , and Server Coexistence
The services subject to the constraint remain on the server, while the rest of the system operates in Teams —and the two must be able to call each other, see each other, and transfer calls. It’s a real architectural challenge.
Our Telephony SolutionsThe version no one talks about
Skype for Business Server SE: Stay on-site, but use a supported version.
Teams is not the only answer, and claiming otherwise does no one any favors. Since July 2025, Skype for Business Server the Subscription Editionhas been available: a subscription-based version with a modern lifecycle. It remains supported as long as it is kept up to date, with no announced end date.
For an organization that must keep its communications in-house—due to data localization requirements, regulatory constraints, client requirements, or an isolated network—this is now the only way to be both on-premises and supported at the same time. All other versions have been discontinued as of October 14, 2025.
What’s really changing: no more major versions to purchase, but rather cumulative updates to install regularly and a subscription to maintain. This is a shift in routine for teams that used to install a server once every five years. A server that’s behind on several updates will be discontinued without notice.
What hasn't changed: the features. The Subscription Edition doesn't include the new features in " Teams "—modern meetings, Copilot, and the integrated contact center. It provides support, which is exactly what we need from it.
How do we get there, according to your version?
- 2019 (updated) On-site Upgrade The Subscription Edition is installed on top of the existing version, like a cumulative update. The server remains the same, and users are not migrated. This is the safest and fastest approach.
- 2019: A Belated Look Back Catch Up First Cumulative Update 8 for the 2019 version is a prerequisite for the migration. Any server that’s fallen behind must be brought up to date first, and that’s a project in itself.
- 2015 or earlier New data center There is no direct path. You have to build the new environment, migrate users, and then dismantle the old one—it’s a complete project, even when staying on-site.
- New Server Using the original 2019 version You cannot install an SE server directly: you must first install the original 2019 version, then upgrade it to the SE edition in a single update step.
The scheduling trap: This last point is the one nobody reads before planning. It doesn’t change the feasibility; it changes the preparation —and it throws off schedules based on the assumption that a new SE server can be set up from scratch in one evening.
Microsoft 365 Local, on Azure Local
Microsoft Productivity, delivered right to your home.
That is why Skype for Business has returned to the agenda. Microsoft 365 Local allows you to run Exchange Server, SharePoint Server , and Skype for Business Server on a Azure Local infrastructure that you fully own and manage: data residency, access control, compliance, with management consistent with Azure.
The point is not to go back in time. It is to have a cloud modernprivate cloud: validated reference architecture, certified hardware, a robust security foundation, and a monitoring plan consistent with Azure, and simplified updates. It’s not an old server in a closet—it’s an enterprise-grade stack that you own.
The fully offline mode is often the deciding factor: the environment operates in complete isolation, with no connection to the cloud public, including the control panel. No online service can provide that.
Microsoft 365 The facility also serves as a business continuity plan: we work in the cloud public on a daily basis, with the ability to continue working on-site if access is cut off. This use case resonates with critical organizations far beyond mere regulatory considerations.
Deployment is handled by a Microsoft-certified partner for this offering. Our specialty is the area that this partner doesn't always cover: voice. We work alongside them—or alongside your partner.
What's in the stack
- Voice Skype for Business Server SE Unified communications and business telephony, including carrier connectivity and session controllers. That’s our scope.
- Messaging Exchange Server SE On-premises messaging, within the same stack and under the same administration.
- Documents SharePoint Server SE Documents, intranet, and processes—all in one place with the rest.
- Base Azure Local, on certified hardware Computing, storage, and networking based on a validated reference architecture. Connected mode, with monitoring and updates via Azure, or fully offline mode.
To be scaled in collaboration with the partner: a large-scale reference architecture distributes the load across multiple Azure Local—some with multiple nodes, others with a single node. Sizing is determined on a case-by-case basis and dictates the overall budget.
The actual scope
A project Skype for Business is not limited to the server.
The server is just the tip of the iceberg. Surrounding it are the carrier connections, session controllers, terminals, call centers, call logging, and the applications that dial numbers—and that’s where post-switchover incidents occur.
| Other Issues to Address | Why It Matters | The Trap |
|---|---|---|
| The operator connection | Why?Incoming and outgoing calls go through session controllers connected to your carrier. They carry the voice, not the server. | The Pitfall: An older version of the controller may not support the SE version. Compatibility should be verified before planning the migration, not during it. |
| The Numbering Plan | Why? Numbers, prefixes, standardization rules, and backup routing—these are what ensure a call reaches the right destination. | The pitfall: Ithas almost always drifted from its original design. To keep it as is would mean continuing a decade of stopgap measures. |
| Emergency Calls | Why?Caller location and emergency number routing are matters of obligation, not preference. | The Trap: This isthe point you realize the day someone dials 144. They test themselves, and the test is documented. |
| Terminals and Rooms | Why? Workstations, headsets, industrial wireless devices, meeting rooms: these are the things users interact with, and they’re the basis on which users judge the project. | The Catch: Somedevices aren't upgraded from one generation to the next. You need to take stock early on, while there's still money left in the budget. |
| Call Recording | Why: Whenretention is mandatory, the storage solution must support the migration, along with its archives. | The Pitfall: Past records must remain readable and exportable. Archive recovery is consistently overlooked in encryption schemes. |
| Applications that call | Why: Record retrieval, automatic switchboard, alert systems, and business applications that dial a number. | The Trap: Theynever give themselves away until they fall. They figure things out by listening to the craft, not by reading a console. |
Our Approach
Prepare, switch, hold—and know how to go back.
Four steps, the same regardless of the project’s direction: toward Teams, toward the Subscription Edition, or toward Microsoft 365 Local. The first step costs you nothing: it results in an offer.
01
The assessment of the situation, and the decision
We monitor everything that's running: version, update delays, session controllers, operator connections, numbering plan, terminals, rooms, call recording, and connected applications.
Then we ask the only question that matters: What’s keeping you at home? Everything else depends on the answer—and if nothing is keeping you there, we’ll tell you so.
What We Deliver
- An inventory of the current situation, including delays in updates
- A numerical comparison of the trajectories over three years
- A Proposed Scope of Work: Scope, Workload, Timeline, Deliverables
02
The Design
Target architecture, sizing, high availability, a revised and streamlined numbering plan, and failover rules in the event of a link failure. For a sovereign project, this is complemented bycoordination with the infrastructure partner: who does what, and where the boundaries lie.
This is also where the decision is made regarding integration with Teams, if part of the company is already using it.
What We Deliver
- Architectural Diagrams and Sizing
- The numbering plan has been revised, documented, and stripped of its workarounds
- The coexistence model with Teams, in both directions
- Notes on the Interface with the Infrastructure Partner
03
The Seesaw
On-site upgrade, new farm, or migration Teams : in all three cases, the rule is the same. Close the window, set the role order, verify the backup, and type “R” before starting.
Users switch over in waves—never all at once on the same morning—and the old environment remains in place until the new one has proven itself.
What We Deliver
- The role-by-role transition plan, including the window and the fallback plan
- Filling in prerequisite gaps, tested in a non-production environment
- The recipe: internal calls, external calls, emergency calls, conferences, terminals
- Training for Administrators and Users
04
Sustained maintenance
A subscription edition is kept up to date; otherwise, it becomes unsupported. We handle this process: monitoring cumulative updates, scheduled deployment, monitoring, and second- and third-level support.
With the same engineers who set up the environment, and a commitment to availability—24/7 or 5/8, depending on your business needs.
What We Deliver
- A service contract: scope, hours covered, response times
- Cumulative updates that are scheduled and tested before deployment
- Monitoring, with alerts sent to us first
- The Exit Plan: What Will Shift to Teams When the Restrictions Are Lifted
Preparing the proposal is free of charge. The detailed audit, architectural diagrams, and failover plans are all part of the scope of work: this is engineering work, not a sales brochure.
Let's talk about your environment
What is your situation?
Six reasons to open this file. If any of them sound familiar, you've come to the right place—and we've seen this happen before.
Your server has been out of support since October 2025
It's still running, and that's exactly why the decision is being put off. There are no more security patches, and there's no paid extension available to purchase.
Your data cannot leave the country
Whether due to regulations, a contract with a client, or an internal policy: the cloud general public is excluded from all or part of your business.
You are studying Microsoft 365 On-campus
The project is led by the IT infrastructure team, and no one internally is familiar with the voice component. That’s exactly where we come in.
Part of the house is already in Teams
We need to ensure that the two systems function properly together—calls, presence, call transfers, and a shared directory—without duplicate administration.
Your phone service can't stop
Switchboard, emergency services, call centers: Shift scheduling is based on your hours and the actual level of urgency, not on a service provider’s schedule.
Can't find the skill anymore?
Engineers familiar with this stack are becoming increasingly rare. An infrastructure that no one knows how to operate is not a sovereign infrastructure.
Why Choose Us
We've been installing this battery since its first version.
Office Communications Server, Lync, Skype for Business, Teams : We have installed each of these generations and migrated from previous versions to the next, for both international organizations and small and medium-sized businesses in French-speaking Switzerland.
That's what matters in a large-scale project: expertise in this stack is becoming scarce, and you can't make up for it just by reading the documentation.
8 000
Users migrated to Teams from Skype for Business and Cisco — 62 offices, 39 countries
3 600
Users switched to direct routing Teams, with the launch of a site in Asia
From OCS
Four generations of the same stack, deployed and migrated
What's included
- End-to-end voice: operator, session controllers, dialing, terminals, rooms, recording.
- A single point of contact for the server, Teams, the contact center, and operations.
- On-site teams: Renens, Sion, Châtel-Saint-Denis. No one opens a support ticket from the other side of the world.
- Transparency along the way: if “ Teams ” is the right answer, we’ll tell you, and the same person will guide you there.
- Federal authorization for staffing services since 2018: We can also assign an engineer to your team.
Frequently Asked Questions
What we're asked to do before we begin.
The six questions that come up on every first date. The answers are intentionally specific: a vague answer at this stage doesn't help anyone.
Skype for Business Server Is he dead?
The 2015 and 2019 versions are: they have been out of support since October 14, 2025, with no paid grace period. The product itself, however, continues: the Subscription Edition has been available since July 2025, and Microsoft has committed to supporting its subscription editions at least through 2035.
What has changed is its purpose. It is no longer a communication platform for everyone—it is the voice component for organizations that need to keep their data on-premises.
Should we go to Teams or stay on the server?
Teams, in the vast majority of cases. Staying on a server is justified only by a specific constraint: data residency, regulatory requirements, an isolated network, or a contractual obligation to a client.
If your main motivation is to avoid a migration, the bad news is that you’ll end up paying more for it later. We prefer to tell you this when we make the offer.
Is upgrading to SE really just a simple update?
From an up-to-date Server 2019, yes: it installs locally, just like a cumulative update, without requiring users to move. That's what makes it so appealing.
But two details change the setup process. Cumulative Update 8 for the 2019 version is a prerequisite; and an SE server cannot be installed directly from scratch: you must first install the original 2019 version, then upgrade it to the SE level. Any schedule that ignores these two points will fail.
What does Microsoft 365 Does Local offer anything more than a traditional server?
An industrial stack rather than a standalone server: Exchange, SharePoint and Skype for Business run Azure locally, on certified hardware, based on a validated reference architecture, with a robust security foundation and a control plan consistent with Azure.
And above all, the fully offline mode, which allows it to operate in complete isolation. That’s what sets a cloud sovereign private network from an old local server.
Can you deploy Microsoft 365 Local on your own?
Microsoft requires that the deployment be carried out by a partner it has certified for this offering. Our role covers the voice workload: telephone architecture, carrier connectivity, session controllers, numbering plan, migration, and operations.
We work alongside the infrastructure partner—whether it’s yours or the one selected for the project. This is a standard division of responsibilities, and it’s specified in the interface notes from the scoping phase onward.
What will happen to our session controllers and terminals?
Session controllers remain in place, provided they are running a compatible version: this is one of the first checks in the audit—and one of the most frequently overlooked.
Devices are sorted: some are compatible, others are not. An inventory is taken at the start of the project, when there is still budget available to replace what needs to be replaced—not the day before the switchover.
Related to this topic
What a project Skype for Business always touches upon.
A communications project is never limited to the server, and sovereignty is never limited to the voice. Here are the pages that build on this one.
Let's talk about it
Tell us what's keeping you at home.
We’ll prepare a proposal at no cost to you—covering the scope, workload, timeline, and deliverables—with no obligation on your part. And if the right answer is “ Teams,” we’ll let you know—the same person you’ve been working with will guide you through the process.