End of most Azure Communication Services in 2028

Introduction

Microsoft published the “Retirement and breaking changes guide for Azure Communication Services” (ACS) on Microsoft Learn, with no Tech Community announcement or associated formal communication. The document confirms the end of onboarding new customers starting October 23, 2026, and the retirement of most ACS services on September 30, 2028.

A complete reversal from the original ambition

ACS was presented at Ignite 2020 as the first fully managed communication platform from a major cloud provider, letting developers add calling, video, chat, SMS, and telephony to their applications, using the same building blocks used internally by Microsoft. Microsoft now states it wants to prioritize communication experiences natively integrated into Teams, Dynamics 365, and Azure, rather than maintaining ACS as a standalone offering, while relying on third-party Communications Platform as a Service (CPaaS) providers to fill the remaining needs.

What’s retired and what gets a breaking change

The guide distinguishes two categories :

1. Retirement : The service, feature, or SDK completely stops being available after September 30, 2028.
2. Breaking change : The service remains available, but its behavior or support requirements change, which may require modifying existing applications.

The following services remain usable after 2028, but only combined with a Teams-aligned service : Call Automation, the voice and video calling SDK, call recording, call diagnostics, audio streaming, and closed captions. Affected teams will need to migrate to updated SDKs and a service such as Microsoft Teams Phone Extensibility.

The special case of high-volume email

Email Communication Services (ECS), the ACS service built on Exchange Online for bulk email sending, is part of the retirement. Microsoft nonetheless built its high-volume external email strategy on this service, all while continuously tightening Exchange Online’s controls to discourage its use for mass distribution.

High Volume Email (HVE), the competing Exchange Online-based service, doesn’t solve the problem as it stands : its ability to send to external recipients was withdrawn before it reached general availability, and Microsoft also plans to remove basic authentication support for SMTP AUTH on HVE, on the same timeline as ECS’s retirement. Organizations that depend on ECS for high-volume external email will therefore need to turn to a specialized third-party platform, or wait for a replacement Microsoft hasn’t announced yet.

Conclusion

ACS’s disappearance as a standalone platform is another signal of technical consolidation at Microsoft, but the lack of formal communication and of a replacement for high-volume external email leaves a two-year deadline with no clear answer. Organizations using ACS for calling, SMS, WhatsApp, or bulk email should review the retirement guide now to plan their migration, rather than waiting for a clarification that isn’t guaranteed to arrive soon.

Sources

Microsoft Learn - Retirement and breaking changes guide for Azure Communication Services

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