The schematic files can be found in the following location. These are Eagle files.
Version 1.1 – This had a small issue where the holes for the 3.5mm jack were too small, so the jacks had to be adjusted to fit. This can still be used, but just bare in mind the jack will need trimming.
Version 1.1 Rev b – I seemed to have misplaced the version 1.1 rev b files that fixed this issue :(. I had to redo the correction in the Eagle files for v1.1 version. I have uploaded these as 1.1RevB-2017 The holes are bigger in this version. As I haven’t produced any boards from the 2017 version I can’t guarantee that its 100% fixed.