Had both Chris, the 56mm sadly went back as it got progressively softer to the edges and corners and suffered from a fair amount of purple fringing. Sharp as a very sharp thing in the centre though. Interestingly it has a USB B port for updates whereas the 13mm has a C port. I did ask the importers, AVM, whether I had an older version but didn't receive a reply. Its built like the proverbial though and I suspect my copy had dodged the QC department.
The 13mm on the other hand is a cracker. It is a phenominal lens and if you swapped Viltrox for FujiFilm ( the crafty tinkers have even put a Red badge on the lens!) you would be forgiven for thinking it was an OEM lens. The metal lens hoods on both are superb.
I was going to replace it with the Sigma 56mm but Amazon UK had the FujiFilm 16-55mm at £829 with 5 interest-free monthly payments. Had one before, sold it, wanted it again. Got it, and it is just superb.
I do hope that your copies are on the ball, they are truly exceptional value for money.