Updates
Why would my phone or iPad automatically update when automatic update is turned off in settings
iPhone 6, iOS 12
Why would my phone or iPad automatically update when automatic update is turned off in settings
iPhone 6, iOS 12
See this about iOS updates and settings --> Update your iPhone, iPad, or iPod touch - Apple Support
This is the app update feature to which elcpu is referring --> How to manually update apps on your Apple device - Apple Support
The setting only controls App updates. iOS system updates are different but you should get an option to install or defer the update.
Updates