WordPress White Screen After PHP Update Fix

Enable WordPress Debugging

The first step is to get more information than just a blank page. Access your site via FTP or your hosting file manager. Locate the wp-config.php file in your WordPress root directory. Open it and look for define('WP_DEBUG', false);. Change false to true. If it's not there, add these lines just before /* That's all, stop editing! Happy publishing. */:
define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);
This will log errors to a debug.log file inside your wp-content directory without displaying them publicly on your site.

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);

Check PHP Version Compatibility

A common cause for a wordpress white screen after php update is incompatibility between your WordPress core, themes, or plugins and the new PHP version. If you upgraded to PHP 8.x, try reverting to the previous version (e.g., PHP 7.4) via your hosting control panel (cPanel, Plesk, etc.). If the site comes back, you know the issue is PHP version related. You'll then need to update all components of your WordPress site to be compatible with the newer PHP version.

Increase PHP Memory Limit

A wordpress white screen memory limit error can occur if your site runs out of allocated memory. This is often seen after updates or migrations when processes require more resources. You can increase the memory limit by editing your wp-config.php file. Add the following line just above /* That's all, stop editing! Happy publishing. */:
define('WP_MEMORY_LIMIT', '256M');
If this doesn't work, you might need to edit your php.ini or .htaccess file, or contact your host.

define('WP_MEMORY_LIMIT', '256M');

Revert Recent Code Changes

If your wordpress white screen after adding code to functions.php or any other core file, the solution is often to undo that specific change. Access your site via FTP and navigate to wp-content/themes/your-theme-name/. Locate functions.php and revert to a previous, working version. If you don't have a backup, carefully remove the last piece of code you added. Be extremely careful when editing core files; incorrect changes can worsen the problem.

wp-content/themes/your-theme-name/functions.php

If the Problem Persists: Seek Professional Help

If none of these steps resolved it, this is where professional help saves time. Debugging a white screen can be complex, involving server configurations, database issues, or deep-seated code conflicts that require expert knowledge. Continuing to troubleshoot without a clear path can lead to further damage or prolonged downtime.