updading WLC model 2504 questions

[ashevillemike]

I am in the process of preparing an update of 75 aps on a Model 2504 that controls a mix of AIR-CAP2702I-B-K9, AIR-CAP2702I-A-K9, AIR-AP2702I-UXK9 aps. 

Here is the controller info:

Manufacturer's Name.............................. Cisco Systems Inc.
Product Name..................................... Cisco Controller
Build Info....................................... Engineering Special
Product Version.................................. 8.5.140.0
Bootloader Version............................... 1.0.20
Field Recovery Image Version..................... 7.6.101.1
Firmware Version................................. PIC 20.0

From everything I've read in the release notes, the system should be good to go to Release 8.5.151.0. However, the previous engineer here said that it was a nightmare updating the 2702I A and B APs last time as they wouldn't take the firmware and a separate firmware was needed for the A and B. I can't find anything related to this issue. 

Can someone let me know if I'm good to go on the update and any potential issues?

Thanks!

[balaji.bandi]

its good to upgrade latest verison to fix some security concerns and bugs.

but you need to understand the new release which you upgrading..

1. read the relase notes.

2. if you are in HA environment, you can upgrade one, so you can role back easily

3. some new code does not support AP. so check the AP comptability list.

4. Once WLC Upgrade, AP also upgrade and reboot, so user will have downtime.

if you have test enviroment, do upgrade and test all working as expected. before you doing in production.

[patoberli]

I suggest going to the very new 8.5.161.0 release. It contains various fixes.
You should not need a second image. I suggest that you pre-load the new image before reloading the WLC, or it will take a very long time until all APs are upgraded and working again.
Release notes: https://www.cisco.com/c/en/us/td/docs/wireless/controller/release/notes/crn85mr6.html

[Leo Laohoo]

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@ashevillemike wrote:

 it was a nightmare updating the 2702I A and B APs last time as they wouldn't take the firmware and a separate firmware was needed for the A and B

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We called it the "double download".  The 2700/3700 would download the firmware, reboot, download the same firmware again, reboot and finally join the controller.  Depending on the size of the WAN link, this entire process takes about 20 minutes (per AP).  

This "feature" is what we call as an "undocumented feature":  Nowhere in any Release Notes will mention about this "double download".