No, not 2015, 2016.
At least that's what game rental site GameFly says! It's listed for North America at the moment, another interesting thing is that this change is very recent, according to this cache , the game was listed for November 3rd 2015.
This is just another way of saying the game may release at the end of 2016 however.
Why did this happen? Was there some sort of problem or delay in the game? Also there's Mario and Sonic at the Rio Games that's coming sometime in 2016 as well. Could they be releasing both games at the same time for fanfare?
NOTE#2: Seems like Japan also got the delay, but according to this tweet , they might get the game in January or February...