I am not aware of my Kobo Vox mis-behaving (so there is nothing to fix). I bought the Kobo on Oct 28 and it had CAN.20111027.172304 installed following the "out-of-the-box" update.
I have discovered since initiating an account with Rdio, and experimenting with INQ, that the battery drained overnight. I unsubscribed from Rdio (TuneIn Pro is radio, not downloadable music, and meets my needs better) and deleted the INQ accounts. But the big saving is simply flipping to Airplane Mode when I'm done for the night.
At Home screen, tap Menu, tap Settings, tap Wireless & networks, tap Airplane mode. Then I hold down the start button to initiate sleep. It shuts off WiFi and saves the battery.
The next day, a click of the Start button restores the Kobo Vox with lots of juice remaining.
I was offered the update and accepted. Now running CAN.20111117.182539 with no apparent problems. The update did everything it said it was doing.
It would be helpful if there was a change log provided somewhere on the Kobo.