iOS 12 last night saw a serious decision made by the Apple company, and it applies to customers all over the world today. More precisely, starting today, iOS 12.3, iOS 12.3.1, iOS 12.3.2 can no longer be installed, Apple forcing customers to install only iOS 12.4 in their own iDevices.
Apple regularly acts in this way, blocking the installation of old versions of its operating systems when it releases new ones. For iOS 12.3, this was expected to happen since iOS 12.4 was released, but no one knew exactly when Apple would make the change.
Usually, Apple leaves about 1-2 weeks after the release of a new version of iOS to block the installation of the old ones, to allow downgrades. Starting today, if you restore for any iDevice, you can only install iOS 12.4, so if you haven't downgraded yet, you can't.
