The 4.4 kernel is out
Linus has, as expected, announced the
release of the 4.4 kernel.

Some of the headline features in this release include
the mlock2() system call with
support for deferred memory locking,
I/O polling in the block layer,
the LightNVM patches for low-level control
of solid-state storage devices,
the ability for unprivileged users to load
BPF programs into the kernel, and much more.
Some more information can be found on the KernelNewbies 4.4 page.