To quote a quite different opera, “it is a curious story”. In 1967 a production of Wagner’s Die Walküre, heavily influenced by Herbert von Karajan  who conducted the Berlin Philharmonic for the performances, opened the very first Osterfestspiele Salzburg. 50 years later it was “remounted” with Vera and Sonja Nemirova directing. I use inverted commas because it’s actually not entirely clear how much was old and how much new. It might be more accurate to describe it as a homage to the earlier version. In any event, it was recorded, in 4K Ultra HD, no less and released as one of the very first opera discs in that format.