WordPress 5.0 Beta 1
WordPress 5.0 Beta 1 is now available!
This software is still in development, so we don’t recommend you run it on a production site. Consider setting up a test site to play with the new version, and if you are using an existing test site be sure to update the Gutenberg plugin to v4.1.
There are two ways to test the WordPress 5.0 beta: try the WordPress Beta Tester plugin (you’ll want “bleeding edge nightlies”), or you can download the beta here (zip).
WordPress 5.0 is slated for release on November 19, and we need your help to get there. Here are some of the big items to test so we can find as many bugs as possible in the coming weeks.
The Block Editor
The new Gutenberg block editor is now the default post editor!
The block editor provides a modern, media-rich editing experience. You can create flexible, beautiful content without writing a single line of code, or you can dive into the modern programming APIs that the block editor provides.
Even before you install WordPress 5.0, you can try the block editor here.
Of course, we recognise you might not be ready for this change quite yet. If that’s the case, you can install the Classic Editor plugin now, which will keep the editor you’re familiar with as the default, even after you upgrade to WordPress 5.0.
Twenty Nineteen
Along with the new block editor, we have a new default theme, called Twenty Nineteen, which takes advantage of the new features the block editor provides.
You can read more about Twenty Nineteen in its introduction post, and follow along with development over on the GitHub repository.
Default Themes
Of course, we couldn’t release a beautiful new default theme, and leave all of our old ones behind. All the way back to Twenty Ten, we’ve updated every default them to look good in the new block editor.
How to Help
Do you speak a language other than English? Help us translate WordPress into more than 100 languages! A known issue: the block autocompleter fails for blocks whose names contain characters in non-Latin scripts. Adding blocks via the plus sign works, and this bug is fixed in the Gutenberg 4.1 plugin. 
If you think you’ve found a bug, you can post to the Alpha/Beta area in the support forums. We’d love to hear from you! If you’re comfortable writing a reproducible bug report, file one on WordPress Trac, where you can also find a list of known bugs.
Minor bug fixes
Add up one by one by one
Then you change the world