We are able to update system apps ourselves but the updates will not be installed in the system partition. The updates will be found in the same area as all the other apps that you download from the play store or install on your device. This is why we are able to uninstall updates (that we manually performed) on system apps until the version that is contained in the system partition.
This. You guys can all install the new camera app fine.. And uninstall it using the "Uninstall updates" option in the app info. It will not overwrite anything or give you any issues when updating to a new version of Android if performed this way.
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