Cisco IOS XE + APSP version numbering confusion

[Network Diver]

Recently we upgraded our Catalyst 9800-400 from 17.9.3 to 17.9.4. The following images were installed in this order.

1. C9800-40-universalk9_wlc.17.09.04.SPA.bin
2. C9800-universalk9_wlc.17.09.04.CSCwh87343.SPA.smu.bin
3. C9800-universalk9_wlc.17.09.04.CSCwh47495.SPA.apsp.bin

The APSP (needed to fix some bugs in old Aironet 2700 and 2800 APs) is then activated but upgrade statistics shows:

Upgrade Status                :  Complete
Percentage Complete           :  100

From Version                  :  17.9.4.202
To Version                    :  17.9.4.27

Started at                    :  11/01/2023 15:19:40 GMT
Ended at                      :  11/01/2023 15:25:45 GMT

Number of APs
       Upgraded               :  19
       In Progress            :  0
       Remaining              :  0

An Aironet 2800 AP shows this images:

ap2800#show version
[...]
AP Running Image     : 17.9.4.27
Primary Boot Image   : 17.9.4.27
Backup Boot Image    : 17.9.4.202
[...]

What is confusing: Did it a version downgrade from 17.9.4.202 to .27 or is the last number to be interpreted as floting point, hence 0.27 > 0.202?

Thanks in advance,

Bernd

[Leo Laohoo]

It is better to just upgrade to 17.9.4a.  

[Network Diver]

No. AP service packs are not included in 17.9.4a and can't be reapplied.

Caution:
Fixes included in 17.9.4 APSP2 for COS AP are not included in 17.9.4a. Further, these patches cannot be reapplied/will not work with 17.9.4a. This image is posted only to assist customer who cannot leverage HTTP/HTTPS Access-lists (ACLs) described in https://www.cisco.com/c/en/us/support/docs/ios-nx-os-software/ios-xe-17/221107-filter-traffic-destined-to-cisco-ios-xe.html. 

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https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/214749-tac-recommended-ios-xe-builds-for-wirele.html#toc-hId-1372699040

But we found out that APSP activation was forgot to commit. It reverted back to old versin after 6 hours. 

[Scott Fella]

The good ol' commit.  That does get folks.  At least you found out why.

[Leo Laohoo]

Have a read of the attached document.  

I hope it helps.