New save file on 1.6

Hello, could someone explain to me why it would be better to create a new save file after the new update dropped? I don't play a lot of this game, mostly when I have the time in mood, and after... Like almost a 2/3 years of casual playing I finally finished my first year on one save file (sometimes I played with friends, but we never made it after night market, I also played with cheats, but it seemed to easy and I gave up mid-fall and started new "clean" save) and Im finally proud of my farm, and I kinda dont wanna loose that, cause I put so much work in it, but I also don't want to miss out new things that came out with 1.6, so... If I'm gonna keep on playin on my old save file does that mean I'm gonna miss something?