iPhone, iPad, and iPod touch owners who have upgraded to iOS 11.3 can no longer upgrade to earlier versions of iOS, such as iOS 11.2.6.
Apple sto ppt routinely signing older versions of software updates as new releases come out to encourage customers to keep their operating systems up to date.
iOS 11.3 is now the only version of iOS 11 that can be installed by the general public on iOS devices. Only developers and public beta testers can download iOS 11.4. This update is currently under beta testing.
We expect iOS4 final release of AirPlay 2 and Stereo support for the HomePod and news on the iCloud as both features are in beta 1 of iOS 11.4 are included again. The support for the charging mat AirPower should now come. However, the device appeared, unlike expected, but not in March 2018.