I have also updated to the same latest firmware and discovered the following :-

You don't need to manually assign the ip address/subnet mask and gateway address on your wireless card or network lan card to gain access to the settings of the device. By updating the device it also features the smart DHCP and domain login ( http://tplinklogin.net) function so you should be able to login by typing in tplinklogin.net directly. I think you were entering 'www' in before since this sends you to the http://ww1.tplinklogin.net website.

When you are logged in you can see your details as normal and how the Smart IP (DHCP) is working assigning an IP address for the router under the lan settings. You can test this by typing this address in your browser and it will bring up the status page. A advantage of this is that you can login into the router while still connected to the net and you don't have to change the settings of the wlan or lan card as mentioned above. I use the device in AP mode.

It also makes it easier to login to this status page on a tablet/phone.

I hope this helps. You could go back to an older firmware but I'm not sure if it safe or not.