Linux Kernel 5.4 Officially Released With ExFAT Support, Kernel Lockdown Feature !FREE!
xfsprogs was update to version 5.15, which enables inobtcount and bigtime by default on filesystem creation. Support for these features was added in kernel 5.10 and deemed stable in kernel 5.15. If you want to be able to mount XFS filesystems created with this release of xfsprogs on kernel releases older than 5.10, you need to format them with mkfs.xfs -m bigtime=0 -m inobtcount=0.
Linux Kernel 5.4 Officially Released with exFAT Support, Kernel Lockdown Feature
The attribute linuxPackages_latest_hardened was dropped because the hardened patches lag behind the upstream kernel which made version bumps harder. If you want to use a hardened kernel, please pin it explicitly with a versioned attribute such as linuxPackages_5_10_hardened.
The linux_latest kernel was updated to the 5.13 series. It currently is not officially supported for use with the zfs filesystem. If you use zfs, you should use a different kernel version (either the LTS kernel, or track a specific one).
The security.rngd module has been removed. It was disabled by default in 20.09 as it was functionally redundant with krngd in the linux kernel. It is not necessary for any device that the kernel recognises as an hardware RNG, as it will automatically run the krngd task to periodically collect random data from the device and mix it into the kernel's RNG.