Log onto your OBiTALK account on their portal. Find your 202 in the list of your installed devices. Click on it. Get into Expert configuration mode (if you previously set up the shortcut method, you can click on the "E" icon; otherwise, click the buttons and (redundant) confirmation to get to expert mode).
Click Status --> System Status. If it doesn't display the complete system status, you may need to reboot the OBi.
You'll then see the firmware version, which should be 3.0.1 Build 4477.
If it's older than that, there are several ways to update it.
Since you have apparently been using the device for a long time, if you haven't configured GV via the OBiTALK portal since spring 2014, you should delete the device off of the portal, factory reset it, then add it back again via the **5 procedure, and then configure Google Voice again, as described in my instructions, here:
http://www.obitalk.com/forum/index.php?topic=8560.msg56460#msg56460Alternatively, you can download the firmware from the OBihai website and then manually upload it to your device, but you do need to do the GV configuration from the portal, not the local interface.
http://www.obitalk.com/forum/index.php?topic=9.0