It appears that "On Now" has been removed - at least from the two devices where it was appearing in my home setups. (An older Roku2 never displayed it)
Last night my wife attempted to use a button that I had programmed to navigate to Home, then to an app on the first row. To get around the On Now feature I had added an extra down arrow to get there. Last night, it failed because On Now was gone. I will happily reprogram my devices to go back to the first row status.
I know that there have been several threads complaining about that feature, so I certainly can't claim credit for anything other than being part of the chorus.
Settings/homescreen on the right "recommendation rows/hide
Go to: Settings, Home Screen, Recommendation Rows, select Hide
That took care of it for me!
I'm about ready to dump my rokus I hate it when companies decide what I want for me.