SKIP GRADES now no longer increases the experience or scrap cost, but only multiplies the amount of levels you get per full experience bar / bought level. This should put towers of level 200+ within reach.
ECONOMIC VICTORY text no longer states that you can get a max damage bonus of 5000%, since you are limited by the overall state of the economy and exchange rates to a mere 2500% anyway.
Most importantly: targeting based on order is fixed! Important lesson: adding squares is not the same as adding lengths.
Hotfix #2.5
Source: Steam Community (opens in a new tab)