WordPress Upgrade and Downgrade

Overview

This guide covers how to upgrade or downgrade WordPress using various methods, including WP-CLI, Softaculous, and the WordPress Dashboard. It also includes troubleshooting tips for common update errors and how to enable verbose logging for debugging.

Methods to upgrade or downgrade WordPress

1. WP-CLI (Recommended)

Upgrade WordPress

1. Log in to the server via SSH.
2. Switch to the user that owns the WordPress install:
   _{su - username}
3. Navigate to the WordPress root directory:
   cd /path/to/wordpress
4. Run the following command:
   wp core update

Downgrade WordPress

1. Log in to the server via SSH.
2. Switch to the user that owns the WordPress install:
   _{su - username}
3. Navigate to the WordPress root directory:
   cd /path/to/wordpress
4. Specify the version you want to downgrade to:
   wp core update --version=x.x.x --force
   Replace x.x.x with required version, example: wp core update --version=6.1.1 --force

2. Softaculous (If WordPress was installed via Softaculous)

Upgrade WordPress

1. Log into your cPanel account.
2. Go to Softaculous Apps Installer.
3. Select your WordPress installation.
4. If an update is available, click the blue update arrows.

5. Create a backup when prompted.

Downgrade WordPress

3. WordPress dashboard

Upgrade WordPress

1. Log into your WordPress Admin area.
2. If an update is available, you will see a notification at the top.
3. Click Please update now to begin.
4. WordPress will download and install the update.

Downgrade WordPress

Troubleshooting common issues

General update errors

Symptom: “The update cannot be installed because we will be unable to copy some files.”

Causes:

• Incorrect file permissions
• Disk space issues

Fixes:

1. Check PHP handler:/usr/local/cpanel/bin/rebuild_phpconf --current
2. Ensure correct ownership and permissions:
   • Files: 644
   • Directories: 755
   • Ownership: user:user
3. Check available disk space: df -h
4. Remove leftover .maintenance file from root if stuck in maintenance mode.

Download failed

Symptom: Download failed. error:0D0890A1:asn1 encoding routines:func(137):reason(161)

Cause: Old OpenSSL version unable to verify SHA-256 certificates.

Solutions:

• Move the site to a modern hosting environment.
• Manually update WordPress via FTP.

Fatal Error: Undefined function during update

Symptom: Corrupt files cause fatal errors post-update, especially blocking wp-admin access.

Fix:

1. Download the latest WordPress installation package from wordpress.org.
2. Extract and replace core directories (wp-admin, wp-includes) via FTP.
3. Visit /wp-admin in a browser to trigger database updates.

Enable debug logging

To capture more detailed logs during updates:

1. Open wp-config.php
2. Add these lines near the top:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', true);
error_reporting(E_ALL);
ini_set('display_errors', 1);

3. Logs will be written to wp-content/debug.log

Summary

Upgrading or downgrading WordPress is a critical task that requires care and preparation. WP-CLI is the most efficient tool for version management, while Softaculous and the dashboard offer convenient UI-based options. Always back up your site, check for compatibility, and troubleshoot carefully using this guide and also take assistance of your development team.