Security updates are typically available for the most current 2 OS versions, and 18 is still officially supported, perhaps until 2026 or 2027. 18.7.3 exists with similar security updates as 26.2. It may not show up on iPhone as an update option without being on the beta 18 channel because they're trying to force people onto 26 using dark patterns, but it shows up on iPadOS without any additional magic.
Thanks for your support. I also find these dark patterns unacceptable and even as a technical person one needs forums to figure out why it only shows the 26.2 update very prominently and not the relevant one. x
We can argue over whether 3 extra taps to access counts as "acceptable" or not, but it's clearly not enough of a hurdle to be considered "not available". Otherwise you might as well count iOS 26 as not being available either, because that needs at least 4 taps to install (settings -> about -> software updates -> install -> enter pin -> ok).
Security updates are typically available for the most current 2 OS versions, and 18 is still officially supported, perhaps until 2026 or 2027. 18.7.3 exists with similar security updates as 26.2. It may not show up on iPhone as an update option without being on the beta 18 channel because they're trying to force people onto 26 using dark patterns, but it shows up on iPadOS without any additional magic.