This blog is updated daily..
A general description is here.
Support for memory profiling is enabled in a standard build (this can be changed by editing config.h).
The help default has been changed to be HTML help rather than CHM help (which is currently unavailable). [Not yet the MSI installer.]
Binary packages are currently installed with all the types of help they contain [but that may change before release]out CHM help if they contain it.
The categories in the installers have been simplified. Now the files to support installation of source packages are always installed (they were now only 0.7Mb), and there are no longer categories 'chtml', 'html/help', 'latex' and 'Rd'.