The official Android 4.1 Jelly Bean update for the Samsung Galaxy S III is coming really soon — some rumors imply an August 29 launch which coincides with the Galaxy Note II event date — and we’ve already seen the leaked ROM in action. That ROM was build I9300XXDLG4 and it looks like there’s a newer one ready for you to try out.
The build on this one is I9300XXDLH4 as of August 14, so it is pretty recent. It seems to pack some improvements to Google Now as well as overall stability enhancements. If you feel brave enough to try this out on your global Galaxy S III (sorry U.S. carrier variant owners) follow the source link below to grab the file and read the instructions (which are pretty easy).
Source: XDA Developers