Thanks for the reply.
I have noticed, though, over the last several days that older messages do seem to just magically dropoff after a couple of days. I am not sure how that dropoff point is determined, though
Does anyone know how to delete text message threads in sync 3 once you have read them? There was a button to do this on the screen in my 2013 MKZ with Sync 2 but no button for that function in either my 2017 MKC or MKX, both with Sync 3