WordPress Release: 3.9.1

TL;DR

WordPress 3.9.1 is a maintenance release that addresses 34 bugs from the 3.9 release. Key improvements include fixes to the new media editor, theme customizer, widgets functionality, and multisite features. This update enhances stability and user experience with particular focus on the TinyMCE editor, media playlists, and RTL support.

Highlight of the Release

• Fixed TinyMCE editor issues with image captions, link buttons, and text selection
• Improved media playlist functionality with better RTL support and text overflow handling
• Enhanced customizer experience with fixes for header images and nav menu widgets
• Resolved multisite issues including case sensitivity regressions and 'www' subdomain handling
• Fixed widget functionality during theme switching

Migration Guide

No migration steps are required for this maintenance release. WordPress 3.9.1 is a standard point release that fixes bugs from the 3.9 release and does not introduce any breaking changes or require special migration procedures.

Users can update through their WordPress dashboard or by downloading the update from wordpress.org and following the standard update procedure.

Upgrade Recommendations

This is a recommended upgrade for all WordPress 3.9 users. WordPress 3.9.1 addresses 34 bugs from the 3.9 release, improving stability and user experience across multiple areas including:

• TinyMCE editor functionality
• Media playlist handling
• Widget behavior
• Customizer experience
• Multisite features

The update is particularly important for:

• Content creators who work extensively with the visual editor and media features
• Multisite administrators who experienced issues with case sensitivity or subdomain handling
• Sites using RTL languages with media playlists
• Anyone experiencing issues with widgets during theme switching

As this is a maintenance release with no breaking changes, the upgrade process should be smooth and risk-free. Users should back up their sites before updating as a standard precaution.

Bug Fixes

Editor Improvements

• Fixed issue where image captions were incorrectly positioned when in paragraphs with other text
• Restored the "active" state of the Link button when an image wrapped in a link is selected
• Fixed cursor style for the resize handle of the editor
• Ensured editor height is saved properly as an integer
• Restored old wordpress_adv_hidden parameter to enable force-showing the kitchen sink
• Prevented uploader triggering when selected text is dragged between windows

Media Enhancements

• Fixed persistence of <track> elements in video shortcodes in TinyMCE views
• Added compatibility layer in wp-playlist.js to avoid errors with unsupported mime-types
• Improved handling of poster images for videos in playlists
• Added proper RTL support for playlists
• Fixed text overflow in playlist captions with display: block and calc() rules
• Used proper translated strings for Video Playlist "drag info" and "Select Poster Image"
• Improved layout of checkboxes in Audio/Video Details modal for better translation support

Widget and Customizer Fixes

• Fixed logic to ensure widgets stay with themes during theme switching
• Improved nav menu widget UX by forcing users to select a menu in the customizer
• Used — Select — instead of -- Select -- for nav menus widget
• Fixed issue where customizer was hiding unrelated 'Remove' buttons
• Allowed skipping cropping header images when image width is smaller than theme width
• Avoided warnings in the process_default_headers() method

Multisite Improvements

• Fixed theme installer redirection and action links post-install in multisite
• Fixed case sensitivity regressions in 3.9
• Restored treatment of 'www' as a special subdomain

Other Fixes

• Fixed shortcode JS to avoid errors when escaped shortcodes include newlines
• Improved admin menu notification selector to prevent color scheme conflicts
• Moved WP_Editors::enqueue_scripts() to admin_print_footer_scripts for customizer compatibility
• Avoided expensive attachment counting query on the post editing screen
• Added missing Dashicons classes to User Admin menu
• Updated version and POT files for bundled themes Twenty Eleven through Twenty Fourteen
• Used ob_end_flush() instead of ob_flush() in Recent Posts Widget

New Features

No significant new features were added in this maintenance release. WordPress 3.9.1 focuses on fixing bugs and improving the stability and functionality of features introduced in WordPress 3.9.

Security Updates

No specific security fixes were mentioned in the release notes for WordPress 3.9.1. This appears to be primarily a maintenance and bug fix release focused on improving functionality and user experience rather than addressing security vulnerabilities.

Performance Improvements

Performance Enhancements

• Optimized Post Editing Screen: Avoided an expensive attachment counting query on the post editing screen, which significantly improves page load time when editing posts with many attachments.

• Improved Script Loading: Changed the timing of WP_Editors::enqueue_scripts() to run on admin_print_footer_scripts instead of admin_footer, which provides better compatibility with the customizer and improves overall script loading efficiency.

• Better Resource Management: Used ob_end_flush() instead of ob_flush() in the Recent Posts Widget for more reliable output buffer handling.

Impact Summary

WordPress 3.9.1 is a maintenance release that significantly improves the stability and user experience of WordPress 3.9. The update addresses 34 bugs across various components of the CMS.

The most notable improvements are in the TinyMCE editor, where issues with image captions, link buttons, and text selection have been resolved. Media functionality has been enhanced with fixes for playlists, RTL support, and better handling of video poster images.

For site administrators, the update improves the theme customizer experience, fixes widget preservation during theme switching, and resolves multisite issues including case sensitivity problems and 'www' subdomain handling.

Developers will benefit from better compatibility with the customizer, improved performance through query optimization, and a more robust handling of editor settings.

Multilingual users will appreciate the improved translations and better layout accommodations for translated text in various UI components.

This release demonstrates WordPress's commitment to refining user experience and ensuring stability across its feature set. While it doesn't introduce new features, it makes the existing functionality work more reliably and intuitively.