layer8 2 days ago

Yes. Following a transition period of 2-3 months after each new major OS version, they withhold security updates for older OS versions from devices that could update to the new major version. The current 18.7.3 will likely be the last iOS 18 update made available to iPhone 11 and up, while the iPhone XS and XR, which can’t update to iOS 26, will continue to receive further security updates for iOS 18. This mode of operation has been the case for many years now.

gruez 2 days ago

Yes. Until a few years ago after a new major iOS version was released (eg. 26 for this year) the last major version (eg. 18 for this year) stopped getting updates, at least for phones that had access to the newer version. That changed a few years ago so that there was a period of overlap where both got updated.

For instance, look at the release history for iOS 12 and 13:

https://en.wikipedia.org/wiki/IOS_12#Version_history

https://en.wikipedia.org/wiki/IOS_13#Release_history

After 13 was released (September 19, 2019) there were no more updates for iOS 12, at least for the devices that support iOS 13.