Windows Phone 8.1 is no longer supported, and that means even Microsoft is dropping services for the platform, including updates and even Store support.
Windows Phone 8.1 seems one of those features being dropped is some elements of Cortana, with the app currently showing the above screen saying:
Change is constant
My clever engineers are making some improvements back at base. By January this page will be retired, and I won’t be using it to show you what’s coming next.I’ll still be there to answer your questions and keep your reminders.
Given that the operating system is now nearly 18 months out of support users can not really complain, though I suspect wrapping up the announcement in cutesy language and the promise of improvement seems somewhat immature.