As far as I know, you can change the mirror.
Just edit /etc/apt/sources.list as a sudoer.
Up to now, I haven't find that the Deepin App Store and the Deepin Printer have any mirror.
Go to /etc/apt/sources.list.d to find them, but make sure you have already do a backup for them before editing them.


中文 
Hello every one i started 2 weeks ago useing DeepIn 20.1 on my laptop and i love it but i still can't change the Mirror to my location everytime i change it it get back automatically to CDN . I would highly appreciate if someone know how to fix it .