"WordPress 6.9 Broke My Site" — How to Recover (2026 Field Guide)

You hit Update Now, the page reloaded — and either the front-end shows a critical error, or wp-admin is unreachable, or Slider Revolution stopped rendering, or Elementor Edit-with shows a blank canvas. Here's the field-tested recovery path: roll back the core in 5 minutes, identify the one deprecated function that did it, patch the offender, and stop it from happening on 7.0.

mysite.com/wp-admin

⚠ Fatal error after WordPress 6.9 update

Uncaught Error: Call to undefined function create_function()
in /wp-content/plugins/revslider/includes/operations.class.php:1842

Plugin: Slider Revolution 6.5.27 · WordPress 6.9 · PHP 8.2

My Blog · wp-admin

PluginsUpdatesTools

✓ Site recovered · Slider Revolution patched

Dashboard

Comment×

Patch deprecated PHP function|

Fix it ⟳ ✓ Done

SimpleReview PRO

waiting for selection…

Detected

Deprecatedcreate_function

Pluginrevslider 6.5.27

Fix plan

Replace create_function() with anonymous function (PHP 7.2+ pattern)

Result

Site loads. Slider Revolution renders. WP 6.9 stays.

✓ PR opened

fix: replace create_function with closure
operations.class.php · 1 line

Click SimpleReview → select the fatal error → Fix it → site recovered without rolling back 6.9

Step 1: Roll Back to 6.8 (10-Minute Triage)

If your site is down and a paying customer is on the phone, get the old core back first. Two paths:

Path A: WP Downgrade plugin (if wp-admin still works)

1. Install the WP Downgrade plugin (free).
2. Go to Settings → WP Downgrade and set WordPress Target Version to 6.8.2.
3. Click Save Changes.
4. Go to Dashboard → Updates and click Re-install Now for the WordPress version. The plugin tricks Updates into pulling 6.8.2 instead of 6.9.

Path B: Manual rollback over FTP (if wp-admin is unreachable)

1. Download WordPress 6.8.2 from wordpress.org/download/releases/.
2. Connect via FTP / SFTP. Delete the wp-admin and wp-includes folders from your site root. Do not touch wp-content or wp-config.php.
3. Upload the wp-admin and wp-includes folders from the 6.8.2 zip.
4. Visit yoursite.com/wp-admin/. WordPress will prompt you to run a database update — click it.

Step 2: Find the Actual Error in debug.log

The "There has been a critical error" page is intentionally vague. The real error is in wp-content/debug.log once you enable logging in wp-config.php:

define( 'WP_DEBUG',         true );
define( 'WP_DEBUG_LOG',     true );    // writes to wp-content/debug.log
define( 'WP_DEBUG_DISPLAY', false );   // hide errors from visitors
@ini_set( 'display_errors', 0 );

Reload the broken page, then read the log:

PHP Fatal error:  Uncaught Error: Call to undefined function create_function()
in /wp-content/plugins/revslider/includes/operations.class.php on line 1842

PHP Fatal error:  Uncaught Error: Class "WP_Widget_Factory" not found
in /wp-content/themes/old-theme/functions.php on line 88

Now you know the file, the line, and the deprecated function. That's 80% of the recovery.

Step 3: Patch the Most Common Breakages

Slider Revolution (older versions)

Symptom: create_function() not found in revslider/includes/operations.class.php. WP 6.9 dropped the polyfill that was bridging the PHP 7.2 removal. Two fixes:

1. Update Slider Revolution to the latest 6.7+ via the plugin's License → Check for Updates page (it ships its own updater, not the WP plugin store).
2. If you can't update (license expired), find the create_function() call in operations.class.php and replace with an anonymous function:

   // Before:
   $cb = create_function('$a', 'return strtolower($a);');
   
   // After:
   $cb = function($a) { return strtolower($a); };

Elementor — custom widgets blank

Update Elementor to the latest 3.x (the team usually pushes a 6.9-compat patch within 48 hours of release). If your custom widgets stop rendering, it's almost always one of:

• A removed Elementor controls API class — check the elementor/changelog.txt deprecation list.
• A jQuery 3.7 incompatibility (WP 6.9 bumped jQuery). Replace $(...).live(...) with $(...).on(...).

Classic widgets / WPBakery

Some classic page builders relied on hooks removed in 6.9 (widget_init arity changed). Updating to the latest version fixes most of them. If the vendor abandoned the plugin, use the Classic Widgets plugin from Automattic as a fallback.

WooCommerce — deprecated hooks

Custom WooCommerce extensions often hook into filters that get renamed across major versions. Search the WooCommerce GitHub repo for the specific hook in your debug.log error and check its since / deprecated annotations.

Cache plugins (W3 Total Cache, WP Rocket, LiteSpeed)

Cache plugins serialize PHP objects to disk. After a WP version bump, those serialized objects can fail to unserialize and trigger fatal errors on every page load. Fix: clear the cache via FTP — delete everything in wp-content/cache/.

Step 4: Prevent the Next Major Update From Doing This

1. Use a staging environment. Most managed WordPress hosts (SiteGround, Kinsta, WP Engine, Cloudways) give you one-click staging. Apply the major update to staging first, click around for 48 hours, then push to production.
2. Disable auto major updates. Add to wp-config.php:

   // Allow automatic minor security patches (6.9.1, 6.9.2)
   // but require manual click for majors (6.9 → 7.0)
   define( 'WP_AUTO_UPDATE_CORE', 'minor' );

3. Subscribe to the WP Core Field Guide at make.wordpress.org/core/. They publish a list of deprecated functions and breaking changes 2-3 weeks before each major.
4. Run PHPCompatibility scans. Install the PHP Compatibility Checker plugin — it scans every plugin and theme for deprecated function calls and tells you what will break before you click Update.

Quick-Reference: What Broke in WP 6.9

How SimpleReview Handles This

If you don't want to spelunk through debug.log and patch deprecated functions by hand, SimpleReview can do it from a single browser click:

1. Install the Chrome extension and open the broken site (or wp-admin if it loads).
2. Click the SimpleReview icon, then click the fatal-error notice or the broken slider.
3. Type "Patch deprecated PHP function" and click Fix it. SimpleReview pulls your debug.log over SFTP, identifies the file and line, and opens a PR with the one-line replacement (e.g., create_function() → anonymous function).

Useful when you have a custom-coded plugin or theme and rolling back the WP core isn't an option (because, for example, 6.9 also shipped a security patch you actually want to keep).

Frequently Asked Questions

Related WordPress Fixes

Sources

• make.wordpress.org/core/ — Core Field Guides per release
• wordpress.org — WP Downgrade plugin
• wordpress.org — Release archive (older versions)
• wordpress.org — PHP Compatibility Checker plugin
• wordpress.org — Debugging in WordPress (WP_DEBUG_LOG)
• wordpress.org — Classic Widgets fallback plugin