After some more testing, it is not problem of the library. It occure every time I try to install the aplication on the device where the 6.80 one was installed.
The delivery metod doesnt matter. B4A bridge, download APK from URL, appupdating. everytime I confirm that I want to install new version and got response that The application cannot be installed.
After uninstall 6.80 version I can install the new version without problems and since then the updating system work normally again