I have qt project and deb package that is built using following command:
dpkg-buildpackage -us -uc
After this action, my package is ready to install. But if I have my package installed and I want install the same or newer, it removes all files which were installed by this deb package. Only action that works is removing old package before installing newer using following command:
dpkg --remove myqtapp
P.S. To install Deb package I use
dpkg -i ...