Gp 3.1 export to MPX file in Spanish does not work for MS Project 2016Std

Exported a file to MPX in Spanish, MS Project says that 2016 is “too new”.
Which version should I use instead then to open these files exported?

(BTW, exporting to XML does crash with MS Project 2016Std Spanish, w10 21H1).

What do you mean as “too new”?

Anyway, we can’t fix MS Project bugs or force it to recognize its own legacy format (MPX). If you share the XML file, I can try talking to the author of MPXJ library, which we use for MS Project import/export, and discussing what might be wrong. No promises, though.

“No se puede abrir este archivo porque se guardó en un formato incompatible con Project 2016. Use una versión anterior de Project para abrir este archivo.”

English: Cannot open this file because was saved with an incompatible format with Project 2016. Use a older version of Project to open this file.
This is the message for the MPX file.
Not sure to be able to share on a forum the XML file. Is there a direct email, please?

MS Project discontinued support of MPX long ago. MS Project 2010 is the last version which could read it, according to Wikipedia

You can find the contact email here:

Thanks. Going out for Eastern… check it when coming back.