Cannot restore backup file of OS 10.2.1.3175

hi, without knowing my OS is 10.2.1.3175 i have backup the data.
Then i reset the phone to factory setting & noticed the OS is 10.2.1.
When restore the backup file error file cannot be restored.
How do i restored the backup file from OS 10.2.1.3175?

p/s. I tried backup n restored for the latest version and successful but not for all backupf ile earlier.

btw my bb or above bb z10 stL 1

What is the OS version of the phone

Posted via CB10

hi..i'm the one posted the thread.
The current version OS is 10.2.1.3247.
I tried to downgrade the OS to 10.2.1.3175 hoping to restore back but couldnt find any apploader. All aploader downloaded cannot be extracted,