WordPress released version 5.0 on December 6th. The update includes a brand new standard theme (Twenty Nineteen) and the undisputed Gutenberg Editor. This block-based editor should make it considerably easier to create posts.
I can no longer adjust the texts on my pages and posts
If you do not want to use Gutenberg for your WordPress website (yet), please install the Plugin Classic Editor after updating. So you can still use the old, well-known editor. You can find this plugin via your WordPress dashboard (Plugins → Add new → search for ‘Classic Editor’) or download it via the plugin page and install it manually.
My website looks ‘strange’
This can be a cache problem. Empty the cache of a caching plugin if you use it. In addition, it may happen that some cache hosting providers also need to ‘flush’ the cache.
Can I still go back to WordPress 5 after updating?
We do not recommend ‘downgrading’ a WordPress installation, if you have a backup of the website then you could restore it. Otherwise, installing the Classic Editor plugin is the best solution.