How to express that a piece of information is the knowledge from a certain date?
Solution 1:
To make it explicitly clear that you aren't saying anything about other times, you can say this:
The house down the street is uninhabited (at least as of 15 March 2019).
The use of at least qualifies the parenthetical information, indicating that you're only expressing certainty about date you specify, but leaving other times still in question.
Solution 2:
"At the time of writing (14 March 2019)..."