Devs: if you're keeping a device on iOS 18/watchOS 10/etc. for testing, now is a good time to go turn off automatic updates!
If you've instead been using your only non-primary device as a 26 testing device, now's a good time to wipe it and restore the old OS onto it if you need it.
Starting next week, it'll get a LOT harder to install these outgoing OSes. Now's the time.