Hello Douglas Henning,
Thank you for posting to the Community. You have some excellent questions. I am a little confused as to wat box you will be upgrading. Will you be upgrading the cable box that the Slingbox is connected to or are you looking to upgrade the Slingbox?
Either way, the Slingbox Solo and forward is compatible with the X1 technology from the Comcast.
If you decide to upgrade the Slingbox, the difference between the Slingbox Solo and the two Slingbox models we currently sell are the following.
The two Slingbox models we have both support HD streaming, Wi-Fi capability, and some other cool features depending on the Slingbox that you upgrade to.
With the Slingbox 500, you have access to the On-Screen menu and other application on the On-Screen menu.
With the Slingbox M1, you have the new Desktop player for the computer, you can setup the Slingbox on a mobile device (Android phone, iPhone or iPad).
Hope this helps,
Sling Media Moderation Team
Since I first posted this message a couple of months back, I did more to X1 and once all the cables got plugged in 100% correct, I have no issues with my Solo.. It's not in HD of course which is really on an impact if I choose to watch via my ROKU App on my big screen at my other location... However, it works just fine on my mobile devices and the screen quality I get there is just fine.... I do have an issue with the App for my Kindle Fire which I would like to use with my ROKU instead of my phone but that paid app has not been upgraded in 2 years which is unacceptable.. I would hope you would just move the current Android App to the Amazon world as well..