According to Linux creator (and lead kernel developer) Linus Torvalds, Linux kernal "6.7 is (in number of commits: over 17k non-merge commits, with 1k+ merges) one of the largest kernel releases we've ever had, but the extra rc8 week was purely due to timing with the holidays, not about any difficulties with the larger release."
This might well be the largest Linux kernel (by size) to have ever been released. It's definitely big. Along with that "bigness" comes several new features, hardware support, and various improvements.
One of the more exciting new features is experimental support for Bcachefs that has been added to the mainline kernel. This is one of the reasons why there were so many commits to the 6.7 kernel. But what is Bcachefs? Simply put, it's a new advanced Linux file system that places a premium on reliability with copy-on-write that provides similar features as Btrfs and ZFS with a cleaner codebase and more reliability. Bcachefs features replication, erasure coding, caching/data placement, compression, encryption, snapshots, and much more.
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Although support for the new file system has been added to the kernel, it should still be considered experimental, so you won't be using it for production-level machines.
Other changes to the file system side of things include:
The 6.7 kernel also adds the option to enable or disable 32-bit emulation for x86-64 kernels. This new ia32_emulation feature will allow unconditional disabling for 32-bit applications at boot time.
As per usual, there's quite a bit going on within the realm of CPU support, such as:
One of the more important graphics improvements comes by way of NVIDIA GSP firmware, which adds much-improved power management and performance for the GeForce RTX 20/30 series of GPUs.
As well, Intel Meteor Lake graphics support is finally enabled by default.
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You can read the official announcement of the 6.7 release for more information or read the merge windows (part 1 and part 2), which give detailed information on all of the changes.
Don't expect the latest kernel to appear in your distribution immediately. Arch Linux should receive 6.7 sometime during the first two weeks of February 2024, Ubuntu should see it for version 24.04, and Fedora 40 (should be released around April 2024) might see this version used by default.