I did some research, it seems that D-link, like most other router manufacturers, quits supporting that last hardware version once a new one comes out. I purchased an A4 version a while back and quickly returned it and got a B1 version after researching this.
The latest scam by everyone, including Cisco! You need a new router every few years. I personally have something like 5 working routers at home, if I went back to DSL and IPV6 did not hit for a while, they would all be GREAT! But with a 20-30 Mbps cable connection, 2 xbox 360's and various other toys the kids have, my older routers are TOAST. I would think the A1 should be good for a while longer though, it is a good solid platform.