Why doesn't work convert from doc to docx many files?

Hi! I need to convert many files from doc to docx.

I try to do it with soffice, but I have one problem.
Use this manual Starting LibreOffice Software With Parameters
If I convert one file it works
C:\Program Files\LibreOffice\program>soffice --headless --convert-to docx --outdir d:\doc\d2 d:\doc\d1\1.doc convert D:\DOC\D1\1.doc → d:\doc\d2\1.docx using filter : MS Word 2007 XML

If I try to convert many files it doesn’t work
C:\Program Files\LibreOffice\program>soffice --headless --convert-to docx d:\doc\d1*.doc --outdir d:\doc\d2 Error: source file could not be loaded

How I can convert many files? Why it doesn’t work?

…-convert-to docx d:\doc\d1*.doc --outdir …

Could it be that d1 is a directory and part of your command line should read: d:\doc\d1\*.doc (according to your one-by-one examples this is the case)?

Why don’t one of you two geniuses (or both) post your perfectly legitmate comments as an answer? No one’s ever going to see this question’s been answered like that.

As for me - I’d prefer to close it as duplicate (if it’s solved by the answer to the linked question)…