i want to upgrade the software version of my wlc4402-50-k9 but i don know how to go about it,cam anyone help with a step by step approach
This should get you started;
You can upgrade the Cisco WLC with either one of these methods:
Command-line interface (CLI)
When a controller is upgraded, the code on its associated access points is also automatically upgraded. When an access point loads code, each of its lights blinks in succession.
Note: Do not power down the controller or any access point during this process. Otherwise, you might corrupt the software image.
The upgrade of a controller with a large number of access points can take as long as 30 minutes. The access points must remain powered, and the controller must not be reset during this time.
Cisco recommends this sequence when you perform an upgrade:
Upload your controller configuration files to a server to back them up.
Turn off the controller 802.11a and 802.11b networks.
Upgrade your controller.
Re-enable your 802.11a and 802.11b networks.
This document provides the steps to follow in order to upgrade the WLC with each of these methods.
Wireless LAN Controller (WLC) Software Upgrade
From this good doc;
Hope this helps!