I diff'ed the kernel sources and it appears the only change was to LZO compression.

Files changed:
crypto/lzo.c
fs/ubifs/compress.c
fs/ubifs/journal.c
fs/ubifs/sb.c
fs/ubifs/super.c
fs/ubifs/ubifs-media.h
include/linux/lzo.h
lib/lzo/lzo1x_9x.c

So they are now using this:
lib/lzo/Makefile
+lzo_compress-objs := lzo1x_compress.o lzo1x_9x.o


"lzo1x_9x.c -- implementation of the LZO1X-999 compression algorithm" - "This file is part of the LZO real-time data compression library."

Wikipedia has a bit of info:
http://en.wikipedia.org/wiki/Lempel-Ziv-Oberhumer