I have a wireless lan controller 2504 with software version of 220.127.116.11. and with 25 license. Currently 9 accesspoint is reisterd and working fine ( AIR-LAP1041N-E-K9 and AIR-LAP1242AG-E-K9 Series).
Now I'm trying to install some new accespoints ( AIR-CAP1602I-E-K9) with ios version "C1600 Software (AP1G2-RCVK9W8-M), Version 15.2(2)JB"...
But the registration is rejected with the message of "Join request received from an unsupported AP". I hope I have to upgrade my controller IOS to version of 18.104.22.168
But my concen is, there will be any issue for current accespoint while I upgrading Controller IOS.
I'm also fear of the current license status after I upgrade.
Also How can I backup current license.
You can download the backup image anytime from Cisco.com.
Your understanding is correct. 1600 series AP's are supported on 7.4 code and above. Also 1041 and 1242 series AP's are also supported on 7.4, so you don't need to worry about the same.
The license would automatically be used on upgraded code.
Taking a backup is pretty easy. You just need to upload the config from WLC GUI under Commands >> Upload file >> Select file type as configuration and enter the details of tftp server.
You can get more info on below link:
Please rate the post if it helps!