Cisco Wireless Controller 2504 Software upgrade

[marramix01]

I am trying to upgrade a Cisco WLC 2504 from 7.0.116.0 to 7.4.121.0, but I am not able to find any information whether I have to upgrade the 'field recovery image as well. I am currently running the following software: 

Software version:  7.0.116.0

with 

Field Recovery Image: 1.0.0

Any help\guidance is always welcome

Thanks, 

marramix01

[kaaftab]

you can find all the relevant information on the link given

http://www.cisco.com/c/en/us/support/wireless/2504-wireless-controller/model.html

[Moin Ilyas]

Please refer: http://www.cisco.com/c/en/us/support/docs/wireless-mobility/wireless-lan-wlan/68835-wlc-upgrade.html

[mohanak]

http://www.cisco.com/c/en/us/td/docs/wireless/controller/release/notes/fus_1_8_0_0.html

If you are using a Cisco 2500 Series Controller and you upgrade to the 7.4.100.0 controller software release and intend to use the Application Visibility and Control (AVC) and NetFlow protocol features, you must install Cisco Unified Wireless Network Field Upgrade Software, Release 1.8.0.0.