It looks like the Viacom contract is going to be ending shortly. The last Dish/Viacom contract was signed on April 21, 2016. I personally can't see this channel, but I see channel 900 is an info channel about a potential dispute. I found it here: DISH TV Online Channel Guide | MyDISH then typed in channel 900 to read the little bit that is there.
I don't see anything on Dish Promise yet, so my guess is that this channel is getting ready in case one happens?
I don't see anything on Dish Promise yet, so my guess is that this channel is getting ready in case one happens?