Later firmware versions introduce improvements in RF (Radio Frequency) optimization, mDNS (Bonjour) gateway services, and better roaming algorithms.
From Cisco.com → Wireless → Wireless Controller → 2500 Series → Software Select AireOS version (e.g., AIR-CT2500-K9-8-5-182-0.aes ). cisco 2500 series wireless controller firmware update
Go to Cisco.com and find the Release Notes for your target version. Look for: Later firmware versions introduce improvements in RF (Radio