I’m sorry I haven’t been able to actively update Wioski as much as I used to. I get a lot of questions about support for Windows 10. You can simply replace the Windows 8.1 WIM file with one made from Windows 10. Hundreds of people are using it with Windows 10 already although it is not mentioned in the documents or the website examples.
However, Wioski does not support the inplace upgrade of Windows 10.