Yes, you can do that with Mif2Go. You produce RTF, then load it into Word. Use a Word macro to update fields then save as .docx. Fully automated, very fast. See User's Guide par. 6.17.1, "Supporting more than one version of Word", for full details including the macro to use.
Nobody can produce .docx files directly that Word will accept because MS is using a "transitional" format for them that they do not document.
Producing docx
Yes, you can do that with Mif2Go. You produce RTF, then load it into Word. Use a Word macro to update fields then save as .docx. Fully automated, very fast. See User's Guide par. 6.17.1, "Supporting more than one version of Word", for full details including the macro to use.
Nobody can produce .docx files directly that Word will accept because MS is using a "transitional" format for them that they do not document.