Earlier quoted context omitted.
It was, but Apple is no longer signing the old releases. ( https://ipsw.me/iPhone14,4 ). I downgraded about 10 minutes after trying iOS 26. Sorry to all who missed the window.
I'm still on 17.7.2, hoping for a jailbreak one day...
It’s only when you’re already on iOS 26 that you can’t downgrade anymore.