Treat anything on Discord as media that will be lost
Do not use Discord to host your files. Do not rely on Discord to preserve your text. DO NOT RELY ON DISCORD FOR ANY KIND OF PRESERVATION OR HOSTING!!
It CAN be lost, it WILL be lost! You must consider Discord as a part of the Core Internet, controlled by one company that hosts the servers.
I thought it was impressive at first that it replaced IRC, but now I am horrified. If the company behind Discord went under today, how many friends would you lose?
How many relationships? How much writing?
You may think this won't happen, but I remember when AIM went down and along with it, entire novels worth of interaction with my oldest friend.
IT CAN HAPPEN TO YOU. IT WILL HAPPEN AGAIN. NO COMPANY IS INFALLIBLE.
Back up your files! Download anything you've saved to Discord NOW, before the API changes go into effect! And DO NOT RELY ON THEM FOR HOLDING IMPORTANT FILES!
Here is a program that lets you download any and all of your discord DMs, your servers, everything. You can set the format (raw text, html (dark and light), and others. You can even download the uploaded files not just the text, though that may be just for the command-line version not the GUI window version.
Please back up your conversations, your stories. I have a backup of everything I care about that runs once a week, with full attachment backups every several months. I write stories on discord, and would be devastated if someone happened to them. You have to have your own local copies of every file you care about.