Today, Apple has blocked the downgrade to iOS 15.4. After releasing iOS 15.4.1 update late last month
As for blocking downgrades, it’s common for Apple to want users to use the latest security systems. In iOS 15.4.1, it focuses on solving problems with abnormally fast battery drain and filling vulnerabilities. safety
Anyone who has not updated to iOS 15.4.1 is recommended to update immediately.
