WordPress co-founder Matt Mullenweg posted yesterday that December 6 is the new target release date for WordPress 5.0. https://make.wordpress.org/core/2018/12/04/new-5-0-target-date/If your site has not been tested or you are not ready for this latest release, one approach is to install the Classic Editor plugin. WPBeginner offers a tutorial on how to do install the Classic Editor. The Classic Editor will be supported until December 31, 2021.https://make.wordpress.org/core/2018/11/07/classic-editor-plugin-support-window/