For the recently released BlackBerry Curve 8520, which released for T-Mobile in the United States, as well as many other carriers across the world. Here’s the official BlackBerry Curve 8520 OS update version 188.8.131.526 which is the latest release you can install as of today. It comes from the carrier BASE, so if you are NOT a BASE customer, you must delete the vendor file located in C:/Program Files/Common Files/Research in Motion/Apploader before loading BlackBerry Desktop Manager, but right after you install the .exe file. Download and install at your own risk. Enjoy.
-by Mac Jadalhack