My impression is that Microsoft is fairly reliable when it comes to supporting old formats and standards. E.g. I can still send Word and Excel DDE commands and

My impression is that Microsoft is fairly reliable when it comes to supporting old formats and standards. E.g. I can still send Word and Excel DDE commands and this is a tech from 90s, Windows 3.1 and stuff. OOXML is certainly more powerful, but it's also more complex.