in As Slow As Possible. The piece will be completed in 2020. I wrote about this piece here, and at that link there is video and there are links to sheet music. This article says,
The sustained notes of the performance are possible thanks to the organ’s customised bellows, and tiny sandbags on strings, rigged to hold each note as long as necessary.
The upcoming change will be the seventh chord in the piece.
There is a sound file of the last note played here.