No, there are currently no methods to hack a Vita on 3.65 or above. At this time, you need 3.60 to install Henkaku on your Vita. There is a method to load Henkaku Enso on 3.65, however it still requires a base firmware of 3.60 to install. However, TheFlow has kernel exploits available for 3.65 and above, which will release sometime after September (no, we don't know exactly when yet). It's currently best to keep your Vita on 3.65, as that is the last firmware that officially supports Henkaku Enso, which is the coldboot version of the exploit (meaning you no longer have to run the Henkaku installer after every reboot, you only need to do it once). If you don't care about having to run the exploit every time you reboot, you can safely update to 3.68 and, once again, wait for sometime after September for TheFlow to release his exploit, as it still works on the current latest firmware.