The Linux 3.13 kernel has been humming along quite nicely and it brings with it many new Linux kernel features, but in the past week there's been too many merges compared to release candidates in past weeks, according to Linus. This release is also longer than normal in that Linus has moved the RC releases back to his preferred Sunday cycle.
Linus wrote, "Things aren't calming down the way they should be, and -rc4 is bigger than previous rc's...Anyway, what that means from a practical standpoint is that I'm going to be *very* grumpy at anybody who sends me unnecessary crap. If it's not regression or marked for stable, then just don't send it to me. Because you *will* be called names if you can't follow those simple rules. Comprende?"
As usual, most of the Linux kernel changes happened to the device drivers and architecture code. More details on Linux 3.13-rc4 can be found via the mailing list announcement.