In the release notes of Homeassistant OS 11.1 it states that kernel 6.1.59 has been implemented. However, after updating (and rebooting) an ‘uname -a’ shows that Linux kernel 6.1.21-v8 is running. Did I miss something ?
# uname -a
Linux homeassistant 6.1.21-v8 #1 SMP Thu Oct 26 14:39:03 UTC 2023 aarch64 HAOS
#
Running on a Raspberry Pi 4B with 4 GB ram.
For the Rapsberry Pi boards we use the latest stable kernel provided by the Raspberry Pi team, which was 6.1.21. The release notes on GitHub reflects changes per board, there is no note about Raspberry Pi which means we are still on the same version we’ve been previously.
Just recently the Raspberry Pi team released a stable release using 6.1.58, so expet the next OS update to bring a newer kernel 
.