New Admin Email Verification
WordPress 5.3 introduces a new administration email verification screen. Currently, you can set the admin email address from Settings >> General. Though that will remain the same, there will be a new verification screen set to pup-up every six months after an admin has logged in. The purpose of this new screen is to verify that the admin email has not changed. This will ensure that emails sent from WordPress are going where they need to go. Examples of these emails include comment approval, new user registration notifications, maintenance messages, etc.
New Admin Stying for Buttons, Forms, and Inputs
WordPress 5.3 is bringing with it several new admin styling changes. Most of these changes are small, and many users may not even notice. One of these changes is the color contrast as shown here:
Another change being added is more detail and definition to the buttons, as you can see here:
These subtle changes are only changes within the CSS. There is no change within the HTML markup. The goal is to bring clarity and a deeper sense of coherency to the admin UI. You can learn more about these WP admin style changes here.
Improvement of Large Image Handling
When WordPress users are uploading photos, many are not taking into account the sizes of their photos. This can increase load times and require more from hosting companies. WordPress 5.3 has the functionality to detect when large images are uploaded and automatically generate a web-optimized maximum size. This will allow all larger images to display crisp and clear, without taking up as much space and potentially breaking the site.
New Default Theme – Twenty Twenty
The new Twenty Twenty theme will become the default theme with the release of WordPress 5.3. Its design is simple and clean and it is heavily focused on the WordPress block editor. Twenty Twenty is minimal by design with the intention of giving freedom to the site builders to create fully customized layouts throughout their entire site.