Gerhard Siegel will sing in the new Elbphilharmonie in November 2017: He will perform Detlev Glanert's "Requiem für Hieronymus Bosch" with the Symphoniker Hamburg conducted by Markus Stenz. Further soloists are: Aga Mikolaj (soprano), Ursula Hesse von den Steinen (mezzosoprano), Nathan Berg (bass) and Leo van Doeselaar (organ). The performance in Hamburg will be the German premiere of Glanert's Requiem.
You can find further information here - unfortunately, there are no tickets left!
In November 2016, another performance of the Requiem with Gerhard Siegel was recorded live at the Concertgebouw Amsterdam. The CD has been released some months ago - you can buy it here.