From a gameplay perspective, players should see more timely reactions from goalkeepers in 'certain in-game situations', and shot accuracy has been reduced somewhat. On top of that, the Amateur and Semi-Pro difficulty options have been toned down, giving newcomers more of a chance to get on the scoreboard.
Ultimate Team bugs such as the game crashing while you were watching a FUT Champions Channel match, and the crowd having the wrong flags while the home team were wearing a certain kit, have also addressed. The Journey: Hunter Returns had one PC-specific bug that saw some people crash on a cutscene in Chapter 5, which shouldn't happen anymore, and players can now delegate contract renewals in Career Mode, too.
A number of other bits and pieces have been added and fixed like Bundesliga matches now having their league specific graphics, and goal net animations are said to be improved. For the whole list, head to the announcement post on the game's forums.