"The way things have gone"? What do you think might have changed that would make them want to delay it? Based on a recent post they were offering someone with an SD only account who called in their choice of a free upgrade to a Genie system, or HD receivers, without changing their monthly fees at all or creating a new commitment. Sounds like it is moving along, the next step will be to start contacting people with SD only accounts or SD receivers on an HD account and offering upgrades and presumably telling them the deadline.
Apparently the Revolution conference is in a couple weeks, I have to think Directv will have some updates to share to dealers that we'll hear about. If they are still planning to do it in 2019 they'll have a date, if it has been pushed back they'd announce that too. Maybe they will even describe it in greater detail, like whether 110/119 will go away, if they'll move some HD channels to 101 or have it carry MPEG4 SD duplicates of everything so RVs will still work with a standard 18" dish, etc.