WordPress Release: 3.9.5

TL;DR

WordPress 3.9.5: Critical Database Bug Fix

This maintenance release fixes a critical bug in the WordPress database handling that was causing all write queries to fail when using certain character sets with non-ASCII characters. The fix ensures proper data structure handling in the wpdb::strip_invalid_text() function, restoring database write functionality for affected users. This is an important update for all WordPress 3.9.x installations.

Highlight of the Release

• Fixed critical database bug affecting write operations with non-ASCII characters
• Corrected data structure handling in wpdb::strip_invalid_text() function
• Improved compatibility with various character sets in database operations

Migration Guide

No migration steps are required for this update. This is a standard maintenance release that can be applied through the WordPress automatic update system or manual update process.

To update:

1. Back up your WordPress site before updating
2. Use the automatic update feature in your WordPress dashboard
3. Alternatively, download the update from wordpress.org and perform a manual update

No database schema changes or special configuration adjustments are needed after updating.

Upgrade Recommendations

Immediate Upgrade Recommended

This update is highly recommended for all WordPress 3.9.x installations as it fixes a critical database handling bug that could prevent write operations with non-ASCII characters.

• Priority: High
• Impact if not upgraded: Continued database write failures when using certain character sets with non-ASCII characters
• Compatibility: Fully compatible with existing WordPress 3.9.x installations
• Recommended for: All WordPress 3.9.x users, especially those working with multilingual content or non-ASCII characters

If you're running an older version than 3.9.x, consider updating to the latest WordPress release for additional features, bug fixes, and security improvements.

Bug Fixes

Database Handling Fix

• Fixed a critical issue in wpdb::strip_invalid_text() where an incorrect data structure was being returned during MySQL conversion checks
• Resolved the problem causing all write queries to fail when using certain character sets with non-ASCII characters
• Applied the fix from WordPress core ticket #32051
• Merged the solution from SVN revision [32261] to the 3.9 branch

New Features

No new features were added in this maintenance release. WordPress 3.9.5 focuses exclusively on fixing the critical database handling bug.

Security Updates

No security fixes were explicitly mentioned in this maintenance release. The primary focus was on resolving the database handling bug.

Performance Improvements

No specific performance improvements were included in this release. The focus was on fixing the critical database handling bug.

Impact Summary

WordPress 3.9.5 addresses a critical bug in the database handling system that was causing write operations to fail when working with non-ASCII characters in certain character sets. This issue particularly affected multilingual sites and those working with international content.

The fix corrects the data structure returned from the wpdb::strip_invalid_text() function during MySQL conversion checks, ensuring proper handling of text with various character sets. This restoration of proper database functionality is crucial for affected sites, as it prevents data loss and operational failures when saving content.

While this is a targeted maintenance release with a single fix, its impact is significant for affected users who were experiencing database write failures. The update ensures WordPress can properly handle international character sets, improving the platform's reliability for global users.