topic Re: WLC 9800-40L Recommended Firmware in Wireless

WLC 9800-40L Recommended Firmware

dimi.kard — Thu, 06 Mar 2025 13:45:30 GMT

Hello,

In about one month we are going to deploy two new cisco WLCs 9800-40L in one of our branches along with Cisco 9130X APs. My question firmware version do you suggest for the wireless controllers ?

Regards

Re: WLC 9800-40L Recommended Firmware

Mark Elsen — Thu, 06 Mar 2025 14:18:33 GMT

- The current recommended release = 17.12.4 ; ref : https://software.cisco.com/download/home/286316412/type/282046477/release/Dublin-17.12.4
However look at the page , and when going for it you should use https://software.cisco.com/download/specialrelease/b5170408cc94b5cb4ffce878e044cf6e
being mentioned under : All 17.12 deployments should run either: 17.12.4ESW13, at this hidden URL,
(which is the same as the link above) or 17.12.4 CCO plus APSP4 (or above), and the CSCwj93876 and CSCwi78109 SMUs
This to have the latest APSP (AP Service Pack) and some bugfixes

Appendix : later on ; when working on the controllers and configuring them you can always validate an intended
or finalized configuration with the CLI command show tech wireless ; and feed the output from that into
Wireless Config Analyzer This is highky recommended and should even be considered mandatory
(Use the full command denoted in green ; do not use show tech-support for this procedure)

Re: WLC 9800-40L Recommended Firmware

Scott Fella — Thu, 06 Mar 2025 14:54:39 GMT

It think most folks will look at what version is the "Gold Code" and use that. I would always ask our Cisco SE about what versions other customers are using and any issues that they have seen. The best way really is to get all that info and have a test environment where you can test and validate that everything is working and even swinging over a small site or isolated area to that test controller so you can get feedback from the users. Its hard to say because some like to have a certain feature that is only on newer code or might have a bug fix that is not yet available on the "Gold Code". Like what @Mark Elsen mentioned, read over the release notes so that you know what have been fixed, what is still open and if any of those might affect you in production.

Re: WLC 9800-40L Recommended Firmware

dimi.kard — Thu, 06 Mar 2025 15:08:03 GMT

Hello,

I think i'll go with the 17.9.6 firmware version. No extra configuration will be required. For authentications ISE will be used, i do not know if you have any objections for 17.9.6 firmware.

Regards

Re: WLC 9800-40L Recommended Firmware

Scott Fella — Thu, 06 Mar 2025 15:22:40 GMT

I don't to be honest. I run multiple test controllers with various versions, but for what we do and what I do in my home lab, I don't really have any issues. You are safe to use a "Gold Code". Also you can open a TAC case to be proactive when you decide to migrate so they can be your second eye to see if they see anything wrong.

Re: WLC 9800-40L Recommended Firmware

Mark Elsen — Thu, 06 Mar 2025 17:01:57 GMT

@dimi.kard >...I think i'll go with the 17.9.6 firmware version.
I would advise against going for 17.9.x because of https://www.cisco.com/c/en/us/products/collateral/ios-nx-os-software/ios-xe-17/ios-xe-17-9-x-eol.html

Consider my initial reply , as best option.
https://community.cisco.com/t5/wireless/wlc-9800-40l-recommended-firmware/m-p/5268241/highlight/true#M281351

Re: WLC 9800-40L Recommended Firmware

Leo Laohoo — Thu, 06 Mar 2025 21:02:26 GMT

We went from 17.9.X to 17.12.4 because we saw many bad things happening in 17.9.X.

Make sure to read the Bug IDs associated to each SMU and APSP and apply which is necessary.

Re: WLC 9800-40L Recommended Firmware

Rich R — Mon, 10 Mar 2025 01:50:56 GMT

I would also recommend against 17.9 because Cisco have long since stopped fixing bugs in 17.9 and recently not even fixing them in 17.12. High severity bugs may still get fixed in 17.12 but we've got one recently which they have even refused to fix in 17.12 saying we have to go to 17.15 for the fix. They even refused to provide a SMU for 17.12! So any bug you find you will just get told to upgrade anyway - better to start with a more supported release - at least 17.12.x but maybe even consider 17.15 which has quite a lot of enhancements.

In terms of what guidance to follow - always check the TAC recommended versions (link below) which gets updated regularly.

Just to clarify - there is no 9800-40L WLC model. There is a C9800-40, and C9800-L-C/C9800-L-F.
CW9800M is the successor to the 9800-40 which goes end of sale at the end of 2025:
https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9800-series-wireless-controllers/catalyst-c9800-wireless-lan-controller-eol.html