Technical Tip: Lost FortiAP connection after firmware upgrade

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Description	This article explains the loss of connection for FortiAP-321C devices after upgrading the FortiOS firmware on the FortiGate. It addresses lifecycle limitations and compatibility issues affecting the FortiAP-321C with newer FortiOS versions.
Scope	FortiAP-321C devices and FortiGate systems running v7.2.x or later.
Solution	Lifecycle Information of the FortiAP-321C: The FortiAP-321C is a legacy model, and its lifecycle status is as follows: End of Order (EOO): January 2, 2020. Last Service End Date (LSED): January 2, 2024. Software End of Support (SW EOS): January 2, 2025. The FortiAP-321C is no longer actively supported for advanced features or updates, and its firmware is capped at version v6.0.6. Compatibility with FortiOS Versions: According to the FortiAP and FortiOS Compatibility Matrix: The FortiAP 321C is compatible with v7.2.x, provided the FortiAP runs v6.0.6. This explains why the AP functioned correctly with the version previously in use (7.2.x). However, after upgrading to v7.4.x, legacy models like the FortiAP-321C are no longer supported. v7.4.x requires more recent AP models or firmware versions, which the FortiAP-321C cannot accommodate. Recommendation: The only alternative to continue using the FortiAP-321C is to downgrade the FortiGate to v7.2.x to maintain compatibility with the FortiAP-321C.(Note that downgrading FortiOS may affect other features or devices in the network. It is important to evaluate the impact before proceeding). Alternatively, consider upgrading to a newer FortiAP model that supports v7.4.x or later. Refer to the FortiAP and FortiOS Compatibility Matrix for a list of supported models and firmware versions: FortiAP-W2 Additional Note: To prevent connectivity issues after upgrades, always verify compatibility between FortiAP models and FortiOS versions using the compatibility matrix before proceeding.