If your organization uses Microsoft Entra Connect Sync (formerly Azure AD Connect), there’s an important deadline you shouldn’t overlook.
📅 September 30, 2026
Microsoft has confirmed that organizations must be running Microsoft Entra Connect Sync version 2.5.79.0 or later by this date.
⚠️ This isn't simply an end-of-support notification.
Microsoft states that all synchronization services will stop working after September 30, 2026 for environments running versions earlier than 2.5.79.0. Synchronization will remain unavailable until the environment is upgraded.
🔍 Check your version now
Don't assume your Entra Connect servers have already been automatically upgraded.
Pay particular attention to environments where:
🔹 Auto Upgrade was disabled
🔹 Auto Upgrade previously failed
🔹 Staging servers are deployed
🔹 Older DR/standby servers still exist
🔹 Entra Connect hasn't been maintained recently
Microsoft specifically recommends manually checking environments where Auto Upgrade was disabled or unsuccessful.
🛠️ What administrators should do
Before September 30, 2026:
🔹 Inventory all Microsoft Entra Connect Sync servers
🔹 Verify the installed version
🔹 Upgrade anything below 2.5.79.0
🔹 Prefer upgrading to the latest supported release, rather than treating 2.5.79.0 as the target
🔹 Validate synchronization after the upgrade
🔹 Check staging and disaster-recovery servers
🔹 Review Microsoft Entra Connect Health agents
🔹 Confirm prerequisite requirements, including .NET Framework 4.7.2 and TLS 1.2
Microsoft also lists 4.5.2466.0 or later as the minimum version for the relevant Entra Connect Health agents.
📦 The Microsoft Entra Connect Sync installer is available through the Microsoft Entra admin center under Microsoft Entra Connect.
☁️ Consider Microsoft Entra Cloud Sync
This is also a good opportunity to review your hybrid identity architecture.
For eligible environments, Microsoft recommends considering Microsoft Entra Cloud Sync, its cloud-managed synchronization solution, as an alternative to traditional Entra Connect Sync.
💡 Bottom line:
September 30, 2026 is a service-impacting deadline—not just an end-of-support date.
If Entra Connect Sync is part of your hybrid identity infrastructure:
Discover → Verify → Upgrade → Test → Monitor
Don't wait for synchronization to stop before discovering an old Entra Connect server is still running.
Microsoft Learn — Entra Connect mandatory upgrade and security hardening
