'Simplification' of 夠
This is discussed extensively in this thread:
http://forum.reviewingthehanzi.com/viewtopic.php?id=7698

A quote


  Because the "simplified" version of this character was made PRC
  standard when the new character lists were published. Even though
  nothing was actually simplified. There was a committee in China tasked
  with simplifying and standardizing written Chinese, when they came
  across this character they noticed there were two common versions of
  the hanzi being used so they had to pick which one will be in the
  official government approved lists. 够 won out.