Should be from the same adaptation. One is movie adaptation and one is series so it should be good.

When We Were Young is a chinese remake version of Korean's Who Are You. So you can try watch this if you like to watch chinese drama. Of course, chinese drama usually tend to prolong their story. This one is too. It have 32 episodes so it a bit long and more detail but if you dont mind about it and want to watch every remake versions of School 2015:Who Are You, then you need to watch this one too!