The only way to restore back to an older OS version would be to reload the software using an autoloader for the corresponding OS version in which you want to run. Note that it may not be possible (nor advisable) to restore a backup from the newer version to the older version as this may cause issues.
In the future, you can turn off automatic updates under Settings > Software Update, tap Advanced at the bottom and toggle the automatically download and install updates option off.
Thanks so much for your help! What happened was I had auto update enabled and noticed the notification. I noticed it had downloaded approx 50% of the update when I turned off the auto update and did a reset on the phone to stop the download.
I then got a notification afterwards indicating the download was complete which was a surprise and that I needed to restart my device for this to take into effect.
At this stage this is where I am. I am willing to give 10.3.1 a shot but want the ability to go back if any performance issues arise.
You can go back with a 10.2.1 autoloader file for your exact model of device but if you want to keep data you'd have to make your own backups of your data files on the phone and use an app like Ultimate Backup for BlackBerry to backup other data such as email messages and texts.
You won't be able to use Link to backup and restore when going back to such an old OS version compared to 10.3.1
Posted from the CB10 app on my BlackBerry Z30 STA100-2/10.3.1.2576 on O2 UK - Activated on BES10.2.5.6
I am sorry to sound like such a newbie but I have heard from many people about using an "auto loader" Truthfully I am not sure what that is??
I usually do OS updates OTA and rarely but sometimes uses BB Link for photos and software/device switches etc.
Will BB Link allow me the ability to go back to 10.2.1 if need be and I have issues with the 10.3.1?
I am a little naive and only like using approved OS's and methods for my phone.
Thx a million
Posted via CB10
Link won't be any use to you. Autoloaders are entire BB10 operating systems in a single file. You run an Autoloader on a Windows computer with your phone plugged in to replace the OS over USB. You'd have to backup what you can yourself without using Link and restore manually after downgrading.
There are many different versions of 10.2.1 you could autoload, some were approved by carrier for release OTA so they are the same as "official" release, some were leaked out of BlackBerry during development. The choice is yours.
Search the forums for a user called Thurask, he has a huge collection of autoloaders on the web to download.
Posted from the CB10 app on my BlackBerry Z30 STA100-2/10.3.1.2576 on O2 UK - Activated on BES10.2.5.6