Did the US supreme court (in 1877) not find?: "No law of Congress can place in the hands of officials connected with the Postal Service any authority to invade

Did the US supreme court (in 1877) not find?: "No law of Congress can place in the hands of officials connected with the Postal Service any authority to invade the secrecy of letters and such sealed packages in the mail; and all regulations adopted as to mail matter of this kind must be in subordination to the great principle embodied in the fourth amendment of the Constitution." (Ex parte Jackson, 96 U.S. 727, 733 (1877)) Why does this not also apply to newly invented forms of communication