
Narrative device. Each author chooses his/her own. I am very happy that he/she made this choice because we have always known that the 4 boys would be forcibly separated at a certain point and I am sure, because I know myself, that the narrative arc of the actual separation will hurt me a lot. Knowing that, instead, there is this light at the end of the angst tunnel < the present that we are now reading > will make me face those painful chapters with more hope in my heart

So originally I think the author only released the future arc on special occasion (like once a year during Christmas) since so many people awaited and asked for it. I believe this is the first time the author releases this many chapters of the future arc over a month.
This would also makes sense because in the high school arc it’s almost time that He Tian leaves to study abroad and Jian Yi will also be taken away. This would connect to the future arc when they return as adults.
I really love 19 days and I've been reading this for the past 8 years, but I don't understand why suddenly stop the high school arc and start the future arc?
Already in the high school arc there were some time skips in the past and in the future that were not very clear, there are some other things to explain as well.
Now we are in the future, as if we are reading a sequel, but I don't understand what's the point of the author (?)
It frustrates me a little bit not having a clear and chronological picture of the story tbh