Air-ct5500-k9-8-3-150-0 Exclusive Link

running 8.3.150.0, these are the most helpful "health check" commands: show sysinfo : Checks uptime and general system health.

: For users requiring ongoing support, Cisco recommends migrating to the Release 8.5.x or 8.10.x software trains, which are the final supported paths for this hardware. Hardware Capabilities (5508 WLC)

5500 series hardware (5508/5510) reached EOL. Do not use this for 5520/8540 unless specifically required; newer 8.5+ code exists for them.

The software version is part of the AireOS 8.3 maintenance train, recognized for its stability and feature-rich environment for "legacy" controllers like the 5508. This version brought several critical enhancements: Overview [Cisco 5500 Series Wireless Controllers]