cPanel MySQL Servers Auto-Upgraded to 9.7: What Happened and How to Recover

What Happened

In mid-April 2026, cPanel's automated update system began pushing MySQL 9.7 to servers enrolled in automatic MySQL updates — affecting an estimated tens of thousands of shared and VPS hosting environments running cPanel/WHM.

The root cause: cPanel's updater queries the MySQL download repository for the "latest" version and applies it without distinguishing between Oracle's two release tracks — LTS (Long-Term Support) and Innovation. MySQL 9.7 is an Innovation release, meaning it's designed for rapid feature testing, not production stability.

The result was predictable: sites that worked fine on MySQL 8.0 LTS began throwing database connection errors, query failures, and authentication issues within minutes of the upgrade completing.

Why MySQL 9.7 Breaks Things

MySQL 9.x sits on the Innovation release track — Oracle's fast-iteration channel that ships new features every few months. These releases are not backward-compatible with the 8.0 LTS ecosystem, and several key changes cause immediate breakage on shared hosting environments:

Are You Affected?

Run these checks to confirm your MySQL version and identify which sites are impacted before attempting a recovery.

Check Your MySQL Version

SSH into your server and run:

mysql --version
# or
mysql -u root -p -e "SELECT VERSION();"

If the output shows 9.7.x, your server was upgraded. Anything showing 8.0.x, 8.4.x, or 10.x.x (MariaDB) means you were not affected.

Check in WHM

Common Error Signatures

Check your site's error logs. These messages confirm a MySQL 9.7 compatibility failure:

# Authentication failure
PDOException: SQLSTATE[HY000] [2054] The server requested
authentication method unknown to the client

# Removed function
Error Code: 1305. FUNCTION db.OLD_PASSWORD does not exist

# Strict mode GROUP BY
Expression #1 of SELECT list is not in GROUP BY clause
and contains nonaggregated column (Error 1055)

# Connection refused (InnoDB crash on startup)
Can't connect to local MySQL server through socket
'/var/lib/mysql/mysql.sock'

Option 1: Downgrade to MySQL 8.0 LTS (Recommended)

This is the fastest recovery path for most affected servers. cPanel's WHM upgrade tool supports switching between MySQL versions — including switching back to an older version.

Option 2: Fix Compatibility Issues (Stay on MySQL 9.7)

If you cannot downgrade — for example, if you have apps that specifically require MySQL 9.x features — these targeted fixes address the most common MySQL 9.7 breakage points.

Fix 1: Re-enable mysql_native_password

Add this to your /etc/my.cnf under the [mysqld] section:

[mysqld]
# Re-enable legacy auth plugin for PHP compatibility
mysql_native_password=ON
default_authentication_plugin=mysql_native_password

# Relax strict SQL mode for legacy applications
sql_mode=STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION

Then restart MySQL:

systemctl restart mysqld
# or on some systems:
service mysql restart

Fix 2: Reset User Authentication Plugin

For existing database users already set to caching_sha2_password, reset them to the native plugin:

-- Replace 'dbuser' and 'yourpassword' with actual values
ALTER USER 'dbuser'@'localhost'
  IDENTIFIED WITH mysql_native_password
  BY 'yourpassword';

FLUSH PRIVILEGES;

-- To generate the command for ALL users at once:
SELECT CONCAT("ALTER USER '",user,"'@'",host,
  "' IDENTIFIED WITH mysql_native_password BY 'SETPASSWORD';")
FROM mysql.user
WHERE plugin = 'caching_sha2_password';

WordPress-Specific Fixes

WordPress core itself is largely compatible with MySQL 9.7, but plugins that use raw SQL or legacy functions are where the breakage occurs. Here's how to diagnose and fix the most common scenarios:

Enable WordPress Debug Mode First

Add to your wp-config.php to surface hidden database errors:

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false); // Keep errors out of frontend

// Then check: /wp-content/debug.log

Common Problematic Plugins

Prevention Going Forward

Once you've recovered, these steps ensure this never happens again on your server.

Frequently Asked Questions