New Widget-related Features

Adding Images: Adding an image within a widget can now be done without the use of code. Images can be added within the widget’s settings.
Adding Videos: Turn any video from your media library into a sidebar widget with the new “Video” widget.
Adding Audio: Any audio in your media library can now be turned into a widget within the widget settings.
Adding Rich Text: Text widgets can now be easily formatted with native rich text editing capabilities.

Link Boundaries

Editing links within content has become slightly easier with a new feature called Link Boundaries. Appending new text to existing anchor text can now be done without having to re-insert the link.

Nearby WordPress Events

The new WordPress 4.8 dashboard has a section for keeping you informed of nearby WordPress events

Removal of Support for WMV and WMA Files

Amongst all the new features being added, WordPress has removed support for aging audio and video formats. File formats requiring the Silverlight plugin will no longer be embedded in content, but can still be displayed as a download link