What you need to know
Microsoft’s lifecycle pages list Skype for Business Server 2015 and 2019 extended support ending 10/15/2025 (6:59:59 AM Pacific). Skype for Business Server Subscription Edition, under the Modern Lifecycle Policy since July 1, 2025, can only be installed as an in-place upgrade from Skype for Business Server 2019.
Potentially affected
Organizations still running on-premises Skype for Business Server 2015 or 2019 for chat, meetings or enterprise voice, and the providers who support them.
DSE recommendation
DSE recommends retiring Skype for Business Server 2015 and 2019 deployments by moving users to Microsoft Teams or upgrading 2019 servers in place to Subscription Edition.
Microsoft’s lifecycle pages list Skype for Business Server 2015 and 2019 extended support ending 10/15/2025 (6:59:59 AM Pacific). Skype for Business Server Subscription Edition, under the Modern Lifecycle Policy since July 1, 2025, can only be installed as an in-place upgrade from Skype for Business Server 2019.
Source facts
Microsoft’s lifecycle pages for Skype for Business Server 2019 and Skype for Business Server 2015 show both under the Fixed Lifecycle Policy with extended support ending 10/15/2025 at 6:59:59 AM Pacific Time; mainstream support ended in January 2024 for 2019 and October 2020 for 2015.
The Subscription Edition lifecycle page shows Skype for Business Server Subscription Edition under the Modern Lifecycle Policy with a start date of 7/1/2025 and lists it as in support. It notes that Subscription Edition can only be installed as an in-place upgrade of Skype for Business Server 2019, so a new server must first be installed with the 2019 RTM code and patched to the Subscription Edition build, build 7.0.2046.810 or higher, in one cumulative update step.
Applicability
Use this for any on-premises Skype for Business Server deployment, including hybrid configurations. Licensing and migration options for Teams and Subscription Edition vary; confirm them with Microsoft or a licensing partner.
DSE recommendation
DSE recommends retiring Skype for Business Server 2015 and 2019 deployments by moving users to Microsoft Teams or upgrading 2019 servers in place to Subscription Edition. Inventory users, enterprise voice routes, gateways, devices and integrations first, move 2015 pools through 2019 or to Teams, and remove external access edges from servers awaiting retirement.
Verification
Track every pool and edge server by version until each is upgraded or decommissioned, confirm DNS records for retired pools are removed, and test calling and meetings after each migration wave.
Official references
Microsoft Lifecycle — Skype for Business Server 2019. Microsoft Lifecycle — Skype for Business Server 2015. Microsoft Lifecycle — Skype for Business Server Subscription Edition. Reviewed October 19, 2026.
Review the official source
Microsoft Lifecycle — Skype for Business Server 2019 · Verified October 19, 2026
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