Comment by layer8
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.
Interesting, I genuinely did not know that. Thank you!