Microsoft has announced plans to shut down its ambitious voice assistant "Cortana" for smartphones.

The announcement is short and straightforward. "On January 31st, 2020, we're ending support for the Cortana app on Android and iOS in your market."

The Alexa and Google Assistant competitor is still available as a mobile app and a function inside the Microsoft Launcher on Android.

The content created by users will be safe since Microsoft promised to move it to another app "Microsoft To Do," a non-voice and much simpler task scheduler.

Cortana will go on working on Windows on PC, and will also be integrated into the Office 365 productivity suite.

This may come as another big blow to Microsoft's AI ambition, after head of AI Harry Shum's sudden departure announcement.

Harry Shum, or Shen Xiangyang in Chinese pinyin, one of the most important figures in Microsoft's AI sector, actively marketed Cortana in China.

Click here to watch Shum's comment on the overuse of the word "AI."

Some experts in China's AI industry speculated that Shum's resignation led to the collapse of Cortana on mobile.

Cortana app has been removed from app stores in China for months.