WordPress Release: 4.9.4

TL;DR

WordPress 4.9.4 is a critical maintenance release that fixes an issue with the automatic update system. The update addresses a regression introduced in WordPress 4.9.3 that broke the automatic update functionality, preventing sites from receiving future automatic updates. This release is essential for all WordPress site owners to ensure their sites continue to receive security and maintenance updates automatically.

Highlight of the Release

• Critical fix for the WordPress automatic update system
• Restores automatic updates for WordPress core, plugins, and themes
• Addresses regression introduced in WordPress 4.9.3
• Fixes issues #43103 and #43235

Migration Guide

No migration steps are required for this update. Site owners simply need to update from WordPress 4.9.3 to 4.9.4, which can be done through the WordPress dashboard or manually.

If your site is running WordPress 4.9.3:

1. Back up your site (recommended before any update)
2. Update to WordPress 4.9.4 through the Dashboard > Updates section
3. If the dashboard update option isn't available, you can manually update by downloading WordPress 4.9.4 from the WordPress.org website and following the manual update instructions

If your site is running WordPress 4.9.2 or earlier, you can update directly to 4.9.4 through the normal update process.

Upgrade Recommendations

Immediate Update Strongly Recommended

This update is critical for all WordPress sites running version 4.9.3. Without this update, your site will not receive future automatic updates, including important security patches.

• Priority: Critical
• Timing: Update immediately
• Affected versions: WordPress 4.9.3
• Testing: Minimal testing required as this is a targeted fix for the automatic update system
• Backward compatibility: Fully compatible with all WordPress 4.9.x installations

If you're running WordPress 4.9.3, you'll need to manually update to 4.9.4 since the automatic update system is broken in 4.9.3. After updating to 4.9.4, your site will resume receiving automatic updates normally.

Bug Fixes

Critical Bug Fix

WordPress 4.9.4 addresses a critical bug in the automatic update system:

• Fixed a regression introduced in WordPress 4.9.3 that broke the automatic update functionality
• Partially reverted changes from [42584] that incorrectly tied plugin and theme updates to core update checks
• Restored the proper code flow to ensure all autoupdates (including plugins and themes) run regardless of whether a core autoupdate is available
• Preserved the timeout improvements from the previous release that allow the system to use cached data when available
• Fixes issues #43103 and #43235

New Features

No new features were introduced in this maintenance release. WordPress 4.9.4 focuses exclusively on fixing the automatic update system regression introduced in the previous version.

Security Updates

While this release doesn't address specific security vulnerabilities, it fixes the automatic update system which is critical for security. Without functioning automatic updates, WordPress sites would not receive future security patches automatically, potentially leaving them vulnerable to security threats. This release ensures that the automatic update system works properly to deliver important security updates in the future.

Performance Improvements

No specific performance improvements were included in this maintenance release. The focus was on restoring the automatic update functionality while maintaining the timeout improvements from the previous release that allow the system to use cached data when available.

Impact Summary

WordPress 4.9.4 addresses a critical regression in the automatic update system introduced in version 4.9.3. This regression prevented WordPress sites from receiving future automatic updates, which could leave sites vulnerable to security issues and missing important bug fixes.

The issue stemmed from changes that incorrectly tied plugin and theme updates to core update checks. This release partially reverts those changes while maintaining the beneficial timeout improvements that allow the system to use cached data when available.

By fixing this issue, WordPress 4.9.4 ensures that the automatic update system works properly for core, plugins, and themes, maintaining the security and stability of WordPress sites. This update is essential for all WordPress site owners to ensure their sites continue to receive important updates automatically.

The fix was implemented quickly after the issue was discovered, demonstrating the WordPress core team's commitment to maintaining a reliable update system for all users.