you must remember that before the iphone ios update you should create a backup file of your iphone data. because when you update your iphone then it automatically delete your all iphone data. but if you iphone data is deleted due to this reasons then you don't worry because you can recover it from itunes backup file. itunes creates your iphone data backup which helps you to recover your data in any data loss situation.
To recover lost data from iPhone without backup:
1) Select the device to scan
2) Enter the DFU mode and then scan your iPhone
* Hold your iPhone and click "Start".
* Press "Home" and "Power" button at the same time when you click "Start",and hold for 10 seconds. The program will count it for you.
* After 10 seconds passing, release "Power" and keep pressing "Home" for another 10 seconds.
3) Preview and recover deleted iPhone data