Icefrog released a second patch update for 6.79 series. DotA 6.79c has a total of 5 bug fixes, 3 heroes added in CM, and 14 minor changes.
Performance was enhanced for older PCs where lag issues were fixed, cost of Midas recipe increased from 1400 to 1550 coins, Monkey King Bar is now toggleable, and many others.
DotA 6.79c is also marked as tournament map which means you can use this version for official gaming.
DotA 6.79c download link