FAQ #25149, published on 2023-11-24
How to remove "permission denied" error appears when updating an Android application installed from the Private Store on certain Xiaomi devices ?
Updating a WINDEV Mobile Android application installed from the Private Store (WDBaaS) may fail with this error:

Application installation failed.
INSTALL_FAILED_INTERNAL_ERROR: Permission denied.

This failure comes from a special setting on these devices. it denies the usual android functionality required for installation. to authorize installation you need : 
  • "Settings",
  • "About phone",
  • "Detailed info and specs",
  • "MIUI version” and quickly tap it seven times until a message saying that you're now a developer appears.
  • go to "Additional settings",
  • "Developer options",
  • turn off option "Turn on MIUI optimisation".