This one is our eighth solely-polish release prior to the next official version, which will be coming out midday tomorrow and dubbed 1.1. There's at least one more release coming tonight, and possibly two (only two if we break something, though).
This one is smaller in terms of the volume of fixes, but it has some really important ones including several core changes that fix multiple bugs that various people were experiencing.
The reason we're doing such frequent releases the last few days is that we want each change to get the maximum amount of time in the hands of players to make sure that we're hopefully not breaking something right before going into a major release.
This is a standard update that you can download through the
in-game updater itself, if you already have 0.500 or later. When you
launch the game, you'll see the notice of the update having been found
if you're connected to the Internet at the time. If you don't have 0.500 or later, you can download that here.