Apple iOS 15.4 upgrade could release as soon as in mid-March, along with a bunch of brilliant new iPhone features, Here are the top two
iOs 15.4 features you should know in advance.

iOS 15.4 Keychain Update 1:- Add Notes to Passwords
Apple iCloud keychain is a pretty good iPhone password manager, but it lack many of the features of full service options such as password, In iOS 15.4 that's about to change, as Apple is adding a couple of  new features to the Keychain.

The first ability to add notes to passwords, this means once you are on iOS 14.5, you can save security questions and other useful data in your keychain, all protected by Your Face ID security.

iOS 15.4 Keychain Update  2:- Username must be saved with new passwords by default
The Keychain is useful because it works across your Apple devices, but in the past it would allow you to save your newly created passwords without a username. This meant that your saved Keychain data was sometimes missing the username. This glitch has been fixed in iOS 15.4, because the updated iPhone operating system will force you to add a username before you can save, by default