BlackBerry OS 126.96.36.1990 has already been leaked for some time for the BlackBerry Torch, BlackBerry Bold 9870 and BlackBerry Curve 3G models. We then started to see carriers slowly started to release official versions. The next carrier to release 188.8.131.520 is O2 UK. So if you're an O2 customer who prefers to install official releases from the network then here's your chance.
Even though this is an official release, be sure to back-up your data before updating your device. You can check out our BlackBerry 101 posts of backing up your data and installing an upgrade if you are unsure.