Skype for Business Server to Microsoft Teams migration: admin guide for 2026

Skype for Business Online is long retired, but some organizations still have Skype for Business Server or hybrid voice workloads to unwind. For admins, the 2026 migration is less about pressing a TeamsOnly button and more about identity, Teams Phone, licensing, compliance, devices, and operational readiness.

First, what changed since the original Skype for Business Online guidance

Skype for Business Online was retired on July 31, 2021, so Microsoft-driven automated upgrades from Skype for Business Online to Teams are now historical, not a current migration path. In 2026, the relevant scenario is usually a remaining Skype for Business Server estate, a hybrid deployment, legacy voice routing, or users still homed on-premises. Also note the lifecycle reality: Skype for Business Server 2015 and 2019 are no longer suitable long-term platforms after their 2025 end-of-support milestone. If you still need an on-premises Skype footprint temporarily, validate current Microsoft support options, but for collaboration and cloud voice the strategic target is Microsoft Teams and Teams Phone.

What the admin is really migrating

A Teams migration is not only a client change. Admins need to account for user coexistence mode, meetings, contacts, phone numbers, policies, devices, emergency calling, voicemail, call queues, auto attendants, contact center integrations, compliance recording, retention, eDiscovery, external access, and reporting. Chat history from Skype for Business is not generally migrated into Teams as Teams chat history. Meeting migration can update supported Skype meetings to Teams meetings, but you should test the Meeting Migration Service behavior in your tenant and communicate clearly with users before cutover.

Identity and hybrid prerequisites

For hybrid environments, start with identity. On-premises Active Directory attributes must synchronize correctly to Microsoft Entra ID, and users should have clean UPNs, SIP addresses, proxy addresses, licenses, and Teams policies before migration. If users are still homed in Skype for Business Server, the hybrid configuration must be healthy enough for Microsoft 365 to recognize the users and apply Teams upgrade state correctly. Review federation, DNS, certificates, OAuth, edge configuration, and directory synchronization before you touch production users.

Current admin path: move users to TeamsOnly

The current admin-controlled approach is to move eligible on-premises users to Teams and place them in TeamsOnly mode. In many hybrid migrations this is performed from the Skype for Business Server management environment using the supported Move-CsUser flow with the Teams move option, while Teams policies are managed with the current MicrosoftTeams PowerShell module and the Microsoft Teams admin center. Avoid relying on screenshots or syntax from 2019; Microsoft has changed portals, modules, authentication methods, and policy surfaces. Before using any command in production, verify it against the current Microsoft documentation and test it with pilot accounts.

Teams Phone planning is the migration workstream that needs the most attention

If Skype for Business was used for Enterprise Voice, build a dedicated Teams Phone plan. Inventory every user number, service number, response group, analog line, common area phone, device, delegated calling setup, emergency location, voice route, normalization rule, dial plan, and SBC dependency. Then choose the right PSTN model: Microsoft Calling Plans, Operator Connect, Direct Routing, or a combination. Direct Routing requires supported Session Border Controllers, certificate and firewall planning, SIP trunk coordination, resiliency design, voice routing policies, and monitoring. Operator Connect can simplify carrier integration, but you still need number, policy, emergency calling, and support-process planning.

Licensing in 2026: check Teams, Teams Phone, and NCE details early

Licensing should be validated before pilot migration, not during cutover. Depending on region, agreement, and purchase motion, Teams may be included in an existing Microsoft 365 or Office 365 suite or licensed separately. Voice commonly requires Teams Phone licensing, and PSTN connectivity may require Microsoft Calling Plans, Operator Connect, Direct Routing carrier services, or a mix. Audio Conferencing, Teams Shared Devices, Teams Rooms, Teams Premium, compliance recording, contact center integrations, and advanced analytics may require additional licenses or subscriptions. If you buy through the Microsoft Cloud Solution Provider program, review New Commerce Experience terms such as annual versus monthly commitments, cancellation windows, and add-on alignment.

Policies, compliance, and governance

Do not migrate users with default policies unless that is intentional. Review Teams messaging, meeting, calling, app permission, app setup, external access, guest access, emergency calling, caller ID, voicemail, retention, sensitivity labels, DLP, eDiscovery, audit, and compliance recording requirements. Teams introduces broader collaboration capabilities than Skype for Business, so governance must address channels, teams creation, external sharing, meeting options, recordings, transcription, Copilot readiness where licensed, and lifecycle management.

Pilot and cutover checklist for admins

A practical pilot should include executives, assistants, heavy meeting organizers, reception or call queue users, mobile users, regulated users, international callers, and users with special devices. Validate sign-in, calendar integration, Teams meetings, Outlook add-ins, contacts, presence, federation, PSTN inbound and outbound calling, emergency calling, voicemail, shared lines, call queues, auto attendants, recording, mobile experience, headset behavior, network quality, and help desk scripts. Use a clear rollback or contingency plan for on-prem voice dependencies, but avoid presenting Skype for Business Online rollback as an option because that service no longer exists.

What happens after migration

After users are in TeamsOnly mode and voice is stable, clean up the old environment. Remove obsolete coexistence assumptions, retire unused Skype policies, decommission legacy meeting add-ins, update training materials, validate DNS and federation paths, remove stale firewall rules where appropriate, and plan the retirement of Skype for Business Server components when no longer needed. Keep operational monitoring in place using the Microsoft Teams admin center, Call Quality Dashboard, usage reports, call analytics, network assessments, and service health alerts.

Admin takeaway

In 2019, many Skype for Business Online upgrades looked like a policy flip. In 2026, the remaining migrations are more complex because they usually involve on-premises dependencies, voice, devices, compliance, and licensing. The cleanest projects treat Teams as a new operating model for collaboration and cloud voice, not just a replacement client.

Key takeaways

• Skype for Business Online migration guidance is historical; current work usually involves Skype for Business Server or hybrid cleanup.
• Use Microsoft Entra ID terminology and validate hybrid identity, SIP attributes, licenses, and policies before moving users.
• TeamsOnly migration should be planned with current Microsoft Teams admin center and MicrosoftTeams PowerShell practices, not outdated 2019 screenshots or commands.
• Teams Phone readiness is critical: number inventory, PSTN model, emergency calling, SBCs, routing, call queues, auto attendants, devices, and support processes must be designed before cutover.
• Licensing must reflect current Microsoft 365, Teams, Teams Phone, Audio Conferencing, Teams Rooms, Teams Shared Devices, Teams Premium, and NCE considerations.

If you still have Skype for Business Server, hybrid voice, or legacy calling dependencies, IT Partner can help assess your environment, design the Teams Phone target state, and run a controlled Microsoft Teams migration with minimal disruption.