Stages of the upgrade journey, with emphasis on the Deployment and Implementation stage

This article is part of Deployment and Implementation stage of your upgrade journey. Before proceeding, confirm that you’ve completed the following activities:

Upgrade from a Skype for Business on-premises deployment to Teams

Follow the guidance in this article if you’ve deployed Skype for Business or Microsoft Lync on-premises and your organization wants to upgrade to Teams either selectively—by using multiple coexistence modes—or all-in. The first step is to set up hybrid connectivity with your Office 365 tenant, and then move your users to Skype for Business Online and assign them the appropriate coexistence and upgrade mode.


If you’re an admin on your Office 365 tenant, you may soon start seeing upgrade options in the Microsoft Teams admin center. Having the option to upgrade doesn’t necessarily mean your organization is ready for this change. For the best user experience, confirm that Teams meets your collaboration and communication requirements, make sure that your network is ready to support Teams, and implement your user readiness plan before upgrading users to Teams.

Step 1: Deploy hybrid connectivity

The key prerequisite for upgrading your users to Teams is to deploy hybrid connectivity. This might involve deploying new external connectivity for your existing Skype for Business or Lync deployment, or simply configuring a hybrid relationship with your Office 365 tenant.

For more information, see Deploy hybrid connectivity between Skype for Business Server and Skype for Business Online

Step 2: Move users to Skype for Business Online

After you’ve completed your hybrid setup, move users to Skype for Business Online.

For more information, see Move users from on premises to Skype for Business Online

Step 3: Assign a coexistence and upgrade mode

After you’ve moved your users to Skype for Business Online, you can assign them the appropriate coexistence mode based on the upgrade journey that your organization has chosen. For more information, see Setting your coexistence and upgrade settings and TeamsUpgradePolicy: managing migration and coexistence.


With Skype for Business Server 2019 and a future cumulative update of Skype for Business Server 2015, you’ll be able to perform Step 2 (moving users to Skype for Business Online) and Step 3 (upgrade users to Teams) in a single step. More information will be provided after Skype for Business Server 2019 is released.

Phone System and Teams upgrade

If you’re transitioning your Skype for Business on-premises deployment from enterprise voice to Phone System with Calling Plans and Microsoft will be your public switched telephone network (PSTN) provider—and assuming that you’ve completed the phone number porting—upgrading your users to Teams will automatically transition inbound PSTN calling to Teams.

If Calling Plans isn’t available, you need to transition your enterprise voice deployment to Microsoft Phone System Direct Routing. To upgrade your users to Teams, see the additional considerations for Phone System Direct Routing.