The 6.15 kernel has been released

Linus has released the 6.15 kernel, as
expected.

So this was delayed by a couple of hours because of a last-minute
bug report resulting in one new feature being disabled at the
eleventh hour, but 6.15 is out there now.

Significant changes in 6.15 include smarter timer-ID assignment to make
checkpoint/restore operations more reliable, the ability
to read status information from a pidfd after the process in question has
been reaped, the PIDFD_SELF
special pidfd value, nested
ID-mapped mounts, zero-copy network-data reception via io_uring, The ability
to read epoll events via io_uring, resilient
queued spinlocks for BPF programs, guard-page enhancements allowing them to be
placed in file-backed memory areas and for user space to detect their
presence, the once-controversial fwctl
subsystem, the optional sealing of some
system mappings, and much more.

See the LWN merge-window summaries (part 1, part 2) and the in-progress KernelNewbies 6.15 page for
more information.