Apple is no longer signing iOS 12.3, 12.3.1, or 12.3.2 for its mobile device lineup as of Wednesday evening, a move that prevents users from restoring to any firmware version older than iOS 12.4, which was released to the general public just last Monday.
It’s not uncommon for Apple to stop signing older versions of iOS, especially a week or two after releasing a new update, but it’s particularly noteworthy that Apple stopped signing at least three iterations of iOS in one fell swoop this week, which doesn’t happen too often.
