No, as long as the updates pushed on the iOS device can be updated directly, the original data will not be cleared after the update is completed, which is equivalent to patching, so you can update with confidence!

Developers who installed the second beta version of iOS 9 found a very useful storage space management function, which can help users with little storage space on their devices install larger operating system upgrade packages.

When trying to install iOS9 on a device with insufficient storage space, a dialog box will pop up to inform the user that some applications will be temporarily deleted to make room for installing the operating system upgrade package. After installing the operating system upgrade package, the deleted application will be reinstalled on the device.

Apple has made a lot of efforts to greatly improve the storage space efficiency of iOS 9. Apple has greatly "slimmed down" the iOS 9 installation package to only 1.3GB, making it easier for users to find the storage space needed to download the upgrade package. The new automatic application deletion function will ensure that almost all customers can upgrade their equipment effortlessly. By installing only the necessary application resources on the device, functions such as application simplification can help to free up the storage space of the device.