WordPress 5 introduces new block based editor called the Gutenberg editor. The default editor for all sites has been forced to be the older editor also called the classic editor. Site administrators can change the editor modes using “Dashboard -> Settings -> Writing” settings:
- Default editor for all users : Classic Editor / Block Editor
- Allow users to switch editors : Yes / No
Switching editor mode on-the-fly is supported, but some hidden data can be left in the text when changing between modes multiple times.