iPhone - cancel 'swipe to upgrade'? I recently had to restore a backup of my iPhone and when I booted it up it the only screen I can get is 'swipe to upgrade'.

I'd really love to avoid upgrading past my current software version at the moment, does anyone know if there's a way to cancel the upgrade?

Thanks in advance for your advice :)
You simply can't. Sorry this is kinda too short to be an answer, but it is.
Apple stops signing older software short after the release of a new version.


  As of Wednesday Apple is no longer signing iOS 9.3.5, effectively
  preventing anyone already on iOS 10 from downgrading to iOS 9.


Source: Apple Insider