This is the first time a core feature has been removed from a WordPress and replaced by a Plugin. There are some concerns about removing a core feature and what will actually occur with the code that is currently on websites. The new “Post by Email” plugin created by Kat Hagan is scheduled to replace the core feature.
WordPress Tavern reached out to WordPress core developer Andrew Nacin and
Andrew Nacin Indicated that “There were some nagging concerns that outright removing the feature from core could inconvenience users who still rely on it. That doesn’t detract from Kat’s work at all. Her plugin is fantastic and it’s definitely a huge improvement over what’s in core now. It was never designed to be pulled into core, but rather to provide us an opportunity to remove what’s in core now.”
For more information on the changes to the “Post by Email” function go to WordPress Codex “Post By Email”