User blog comment:MisterWoodhouse/This Month at Fandom - October 2019/@comment-40243961-20191031165136/@comment-24006128-20191031165609

The features themselves will be removed, as the underlying code is not viable for the newer platform. The replacements will solve for the same use cases as well as some additional ones, based on user feedback. It's like how some games for Windows XP can't run on Windows 10. It's easier to remaster or remake them than to make them compatible.