If you are using Cisco 9800, you know that Cisco stopped supporting Wave 1 (17xx/27xx/37xx) APs beyond 17.3.x codes. Here is a slide from a recent Ciscolieve 2023 presentation (BRKEWN-2338) that listed 9800 IOS-XE recommendations.
However, Cisco recently announced wave 1 AP support in IOS-XE 17.9.3 code (In fact I heard about it the first time in the above Ciscolive presentation). This will help customers who got wave1 APs to adopt 9800 migration faster and also move forward with their 9800 WLC firmware without stuck in 17.3.x code.
Here is the release note of 9800 in 17.9.3 which highlighted the support of Wave 1 APs. Features wise you still get 17.3.x parity with those Wave 1 APs even you with 17.9.3.
One reason for such a decision is the last day of software maintenance for 17.3.x code listed 31st March 2023. For a lot of customers who had Wave 1 APs stuck in 17.3.x code as they could not upgrade their AP fleet in time (budget constraints, supply chain issues during the pandemic, etc). Now last day of 17.3.x maintenance release approaches they have to go to different codes to get proper bug fixes, and security patches on the 9800 codes they run.
I have tested my lab 3702 to get registered & clients can connect, In your case, you have to test it in your environment and upgrade your 9800 to 17.9.3 (if you are with 17.3.x and got wave-1 APs on your 9800). That will provide a code that gets maintenance fixes for your 9800 firmware at least for the next couple of years.
When you choose a firmware version to upgrade, always go with an extended maintenance release code train. Both 17.3.x & 17.6.x EoL has been announced. In that way planning to upgrade to 17.9.x is something you should consider. As of March 2023, we got its third maintenance release (17.9.3). Typically I would start using it in production environments when you got 3rd or 4th maintenance release of a major code train.
Here are some CLI commands (from WLC & AP end) that you can use to verify
C9800-2#sh ap name AP1-3702 config general | in Ver|Model Software Version : 220.127.116.11 Boot Version : 18.104.22.168 Mini IOS Version : 22.214.171.124 AP Model : AIR-CAP3702I-Z-K9 IOS Version : 15.3(3)JPN2$ AP1-3702#sh capwap client rcb AdminState : ADMIN_ENABLED Primary SwVer : 126.96.36.199 Backup SwVer : 0.0.0.0 NumFilledSlots : 2 Name : AP1-3702 Location : default location MwarName : C9800-2 MwarApMgrIp : 192.168.100.20 MwarHwVer : 0.0.0.0 ApMode : Local ApSubMode : Not Configured OperationState : UP CAPWAP Path MTU : 1421 Link-Encryption (AP) : Disabled Link-Encryption (MWAR) : Enabled Prefer-mode : IPv4 LinkAuditing : disabled AP Rogue Detection Mode : Enabled AP Tcp MSS Adjust : Enabled AP Tcp MSS size : 1250
Hope this is good news for most of you.