Apologies for resurrecting an already zombie post, but I've got a PSA for people with this router.
TP-Link apparently released a HW version 3 sometime early this year (2017). I first noticed references to it on their support site some time in February. In addition to "updated" documentation, they released the initial firmware image, which is dated Aug. 3, 2016.
I've got a HW version 2 of this router, which hasn't seen a firmware update since August 2014. I stopped using the router mid 2016 because of the apparent lack of support. Back when they transitioned from hardware version 1 to version 2, their support recommended everyone with version 1 update to the version 2 firmware to fix some big issues. This made me wonder if the new firmware for version 3 was compatible with hardware version 2.
Since I wasn't using it, I decided to take a chance and try updating it. I plugged in the router, did a factory reset, uploaded the new firmware, and was delighted to see the newer firmware is successfully installed with the older hardware. I did another factory reset after the update to make sure everything was written over correctly. Outside of a newer GUI (which is substantially less buggy and more performant than the old firmware), there don't appear to be any new features nor any older features changed or removed.
I haven't done any extensive testing on it yet, but with 'newer' software I'm thinking about using it again. Just thought I'd share for anyone who might still be using these.
Edit: Sorry, forgot to include a link to the site.
http://www.tp-link.com/us/download/TL-R600VPN_V3.html#Firmware