WordPress Release: 4.4.3

TL;DR

WordPress 4.4.3 is a maintenance and security release that addresses several bugs and security vulnerabilities in WordPress 4.4.2. This update includes fixes for email functionality, search queries, emoji compatibility in IE11 and Safari, iframe loading improvements, and several security enhancements. The release also updates external libraries like MediaElement.js and Plupload to their latest versions.

Highlight of the Release

• Fixed email functionality with corrected compact() usage in wp_mail()
• Improved search queries by ignoring search terms consisting of a single dash
• Enhanced emoji compatibility for IE11 and Safari browsers
• Added security improvements with nonces for AJAX actions
• Updated external libraries including MediaElement.js and Plupload

Migration Guide

No specific migration steps are required for this maintenance release. WordPress 4.4.3 is a backward-compatible update that fixes bugs and security issues without introducing breaking changes.

To update to WordPress 4.4.3:

1. Back up your website files and database before updating
2. Update through the WordPress admin dashboard (recommended) or via manual update
3. If you're using caching plugins, clear your cache after updating

No changes to themes or plugins should be necessary as a result of this update.

Upgrade Recommendations

This is a security and maintenance release that addresses several important bugs and security vulnerabilities.

Immediate upgrade is strongly recommended for all sites running WordPress 4.4.2 or earlier in the 4.4 branch. The security improvements in this release help protect your site from potential vulnerabilities, while the bug fixes improve overall stability and compatibility.

The update process should be straightforward with no expected compatibility issues. As always, backing up your site before updating is recommended as a best practice.

Bug Fixes

Email Functionality

• Fixed compact() usage in wp_mail() function to ensure proper email delivery

Search Functionality

• Fixed search queries that include a single dash character, which previously caused searches to fail due to incorrect conversion to "NOT LIKE '%%'" clauses

Emoji Support

• Fixed IE11 compatibility issues with MutationObserver implementation by joining text nodes back together when encountering HTML template interpolation symbols
• Fixed diversity emoji check in Safari by addressing the Uint8ClampedArray.toString() method compatibility issue

Embeds

• Improved iframe loading for embedded content with more accessible methods for initially hiding iframes
• Enhanced display logic to only show iframes after successful loading

Taxonomy Handling

• Fixed taxonomy functions to work correctly with taxonomy names containing special characters

New Features

No significant new features were introduced in this maintenance release. WordPress 4.4.3 focuses on bug fixes, security enhancements, and compatibility improvements to the existing feature set.

Security Updates

AJAX Security Improvements

• Added nonce verification to AJAX action for script compression settings
• Added nonce verification for updating wporg_favorites user meta field

Multisite Security Enhancements

• Improved validation for new email address confirmations in multisite environments
• Enhanced escaping in network settings to prevent potential security issues

HTTP Request Handling

• Improved detection of valid IP addresses for better security in HTTP requests

Shell Command Handling

• Switched from escapeshellcmd to escapeshellarg in Snoopy for more semantically correct and secure argument handling

Performance Improvements

Iframe Loading

• Improved how iframes are loaded after being initially hidden, using more efficient and accessible methods
• Enhanced the display logic to only show iframes when they have successfully loaded, reducing visual disruption

External Libraries

• Updated MediaElement.js from upstream, which may include performance optimizations
• Updated Plupload from upstream, potentially improving file upload performance

Impact Summary

WordPress 4.4.3 is primarily a security and maintenance release that addresses several important issues in the 4.4 branch. The impact is largely positive, with improved security through added nonces for AJAX actions, better email validation in multisite environments, and enhanced IP address detection.

For everyday users, the most noticeable improvements will be fixed search functionality when using dashes, better emoji support across browsers (especially IE11 and Safari), and improved iframe loading for embedded content. Developers will benefit from fixes to email functionality, taxonomy handling with special characters, and updated external libraries.

This release doesn't introduce any breaking changes or require modifications to existing themes or plugins. It's a straightforward update that enhances security and stability while fixing several bugs that could impact user experience.