I'm on the west coast and it's 7pm. I got the same email and was surprised that no HD. so I called dish, they guy said he had NO information on this. he said he gets updates every day, and he sees nothing about AHC being in HD. typical. direct tv is no better, comcast is no better. they all have us by the balls and there is nothing you can do.
I actually tried to switch to direct tv this week so I could get NFL sunday ticket. but the dish installer said direct tv could not install the dish on my house because of trees blocking the signal. but he said you can get stand alone NFL sunday ticket streaming if you can't use a dish because of line of sight issues. so I called direct tv about this. got transfered 4 times, and nobody knew anything about this or would not help me, or just flat out lied to me. but if you go to their website, it's right there, NFL sunday ticket.tv and it says available to people who can't use a dish. but nobody in customer service would help me or denied it even existed! why? because they have been told to not sell it to you because they want people to buy their packages and 2 year contracts. totally crazy.
I used chat today 07/12/2017 and was told AHC HD is not offered. I told them about the email, plus the AHC channel page says HD. They said would check again. Came back and said tomorrow. They email I received 07/11/2017 at 4:07 PM said tomorrow, so that would be the 12th, not the 13th.