WordPress 4.0, “Benny,” was released on September 4, 2014. Here’s a summary of “What You Need to Know” from an article by Adrian Spiac and posted at CozmosLabs:
- More Focus on Content — Improved WYSIWYG text editor
- Visual Media Embeds — “As soon as you’ve entered a URL, the video, tweet or any other embedable media will load directly in the editor box.”
- Improved Media Library — “A grid view, giving you a much better overview of your media files. [and a] new details preview, which speeds up viewing and editing any media file.”
- Language Selection UI — Improved selection of language for your WP install
- Good news for WordPress Developers — Improved development options
Find information on all the updates and releases, all the way back to its earliest releases in 2003, at wordpress.org/news/category/releases/