Originally Posted by
waw case Go to device Settings>Apps and select the app in which you want to uninstall updates. If it is a system app, and no UNINSTALL option is available, choose DISABLE. You will be prompted to uninstall all updates to the app and replace the app with the factory version which shipped on the device. Once finished, if you still wish to have access to the app, you may need to select ENABLE.
This isn't the same as uninstalling a system update, like rolling back from Pie to Oreo. Your steps only work on pre-installed stand alone apps, which isn't the same. So it would work on something like Chrome or a carrier's account management app, but you would still be operating on the same OS version.