There are 5 new major features/updates for this new version.
1. Introducing a modern new design
WordPress 3.8 has a new facelift for the entire admin dashboard. Bring on a bigger, bolder, more colorful design! Now it has modern aesthetic, clean typography and refined contrast.
2. WordPress on every device
When responsive design has become a must for all mobile/tablet users, WordPress as the most popular Open Source blog platform, has followed the trend as well. No matter what you use, WordPress will adapt and you’ll feel right at home.
Now WordPRess is sharper than ever with new vector-based icons that scale to your screen. By ditching pixels, pages load significantly faster, too.
3. Admin color schemes to match your personality
WordPress included 8 new admin color schemes so you can pick the one that suits you best. New color schemes can be previewed and changed from your Profile page.
4. Refined theme management
The new themes screen lets you survey your themes at a glance. Now, with smoother widget experience, you can drag-drag-drag or scroll-scroll-scroll without much effort.
5. Twenty Fourteen, a sleek new magazine theme
Turn your blog into a magazine
Create a beautiful magazine-style site with WordPress and Twenty Fourteen. Choose a grid or a slider to display featured content on your homepage. Customize your site with three widget areas or change your layout with two page templates.
Now you can almost do anything with WordPress in few clicks.