https://bugs.winehq.org/show_bug.cgi?id=57217
--- Comment #2 from Andrew Nguyen arethusa26@gmail.com --- Can you confirm that WfConverter on Windows has a different behavior from what you are seeing on Wine?
On Windows, I found what appears to be an example .sdlxliff from https://github.com/RWS/trados-studio-api-samples/blob/master/LanguagePlatfor... and downloaded the repository. With 32-bit or 64-bit WfConverter downloaded from your provided link, I selected the .sdlxliff file as an input file and pressed Start in the application. As a result, I see the same "Not yet implemented" error message that is shown in the attached screenshot.
Therefore, unless you can provide further information, I think this bug should be closed as invalid.