At the top of the 9700/Bold2
forum there are links for the most recent OS for that device. Doesn't matter if it's from a different carrier as long as it's the 9700 model BlackBerry.
The FAQ has lear instructions on upgrading your OS and if you follow them exactly you should be good to go. Pay particular attention to the step for deleting the vendor.xml file. I forgot this step and the install ground to a halt, causing me to almost tear my hair out (profile pic may suggest otherwise).