But docx is also an open source standard. It was accepted by the Ecma International standards committee as office Open XML in 2008. Microsoft also pledged in th

But docx is also an open source standard. It was accepted by the Ecma International standards committee as office Open XML in 2008. Microsoft also pledged in their Microsoft Open Specification Promise to... > Microsoft irrevocably promises not to assert any Microsoft Necessary Claims against you for making, using, selling, offering for sale, importing or distributing any implementation to the extent it conforms to a Covered Specification So it seems to be on the same ground as the odt format