This update has been uploaded to the beta branch. If you want to play with the new pack now, right-click on Epic Auto Towers in your Steam library, then select "Properties..." -> "Betas" -> "beta - Beta Branch." 
In the library, the game will now look like this:
Version 0.98
Major Inferno Tower Update!
New Inferno Tower upgrade mechanic on round three
New tower: Executioner Tower
Improvements for Imp Towers, Cerberus Towers, Ration Towers, and Cauldron Towers