This will be Linux 3.16, due to be released in early August. Release candidates for Linux 3.16 are already packaged and available in the experimental suite.
If you maintain a package that is closely bound to the kernel version - a kernel module or a userland application that depends on an unstable API - please ensure that it is compatible with Linux 3.16 prior to the freeze date (5th November, 2014). Incompatible packages are very likely to be removed from testing and not included in 'jessie'.
My kernel module package doesn't build on 3.16 and upstream is not interested in supporting this version. What can I do?
The kernel team might be able to help you with forward-porting, but also try Linux Kernel Newbies or the mailing list(s) for the relevant kernel subsystem(s).
There's an important new kernel feature that ought to go into jessie, but it won't be in 3.16. Can you still add it?
Maybe - sometimes this is easy and sometimes it's too disruptive to the rest of the kernel. Please contact the team on the debian-kernel mailing list or by opening a wishlist bug.
Will Linux 3.16 get long term support from upstream?
The Linux 3.16-stable branch will not be maintained as a longterm branch at kernel.org. However, the Ubuntu kernel team will continue to maintain that branch, following the same rules for acceptance and review, until around April 2016. Ben Hutchings is planning to continue maintenance from then until the end of regular support for 'jessie'.