Teams Phones impacted by retirement of legacy auth infrastructure: HARDWARE UPGRADE REQUIRED - Retirement in effect

Updated August 5, 2026: We have updated the content. Thank you for your patience. 

[Introduction]

Microsoft has retired support for several legacy Teams Phone devices that depend on authentication infrastructure reaching end of support. This retirement took effect on August 1, 2026.

Any remaining impacted devices are now unsupported and may no longer be able to sign in, make calls, or receive calls. Organizations with remaining impacted devices should replace them immediately to avoid or remediate service disruption.

Since hardware replacement requires procurement, provisioning, and user rollout, we recommend starting the replacement process immediately to reduce operational impact.

[What you need to do now]

• Review your Teams Phone hardware inventory and identify any remaining impacted models.
• Replace affected devices with currently certified Teams Phone hardware as soon as possible.

No automatic upgrade path is available; hardware replacement is required.

Impacted models include:

• Poly Trio 8500/8800
• Yealink T55/T55A
• Yealink T56/T56A
• Yealink T58/T58A
• Yealink CP960
• AudioCodes C448HD
• Yealink MP52
• Yealink VP59
• AudioCodes C450HD
• Crestron UC‑2
• Crestron UC‑P8
• Crestron UC‑P10
• Crestron UC‑P8‑C
• Crestron UC‑P10‑C

Replacing affected devices ensures continued Teams Phone functionality, security alignment, service reliability, and access to supported Teams-certified hardware.

Learn more: 

• Modern Lifecycle Policy | Microsoft Lifecycle Policy | Microsoft Learn