For the correct version, it's quite easy to establish 6 boxes, and then some fishy moves will solve all 81 cells, and

then you can determine the final 3 boxes...

Solution:

976583124

419238576

521647938

754961283

238754691

682319457

147825369

395476812

863192745

Solution picFor the incorrect version, you can determine all 9 boxes quite easily early, but then you can only progress to

this state, where a total of 4 different solutions are possible:

976485123

419538276

521647938

754961382

238754691

682319457

147823569

395276814

863192745

976583124

419238576

521647938

754961283

238754691

682319457

147825369

395476812

863192745

976485123

419532876

561247938

754961382

238754691

682319457

147823569

395678214

823196745

976485123

419538276

561247938

754961382

238754691

682319457

147823569

395672814

823196745

Note to self: next time Uwe release a puzzle, wait at least one month for others to report any typos etc, because a lot of time can be wasted on an invalid puzzle!