@highfigh that model has no ethernet port or wifi. My 2310ci is 12 years old and that 2809ci seems to be similar in features.
Manual is found here. I wish they would put copyright dates on the literature to make it easier to date these things.
DOH! When I see the CI at the end of the model number, my mind goes to "Those are for the Custom Integration channel, so they have features used for installations that are more technically involved than most" and then, I realize that it's basically a typical AVR with a couple of 12V triggers and am RS-232 port. Big whoop. It seems that the ethernet/web were added in 2011.
Denon's model year can be determined in many cases by looking at the model number- this would have been from 2009, yours is from 2010. The three digit model numbers, sold through distribution only, aren't quite as easy, but a model like the AVR-991 would have been from around 2011. I'm trying to find some problems with an AVR-2313CI and that was from 2013.