Resolve WordPress database update prompt after version upgrade

Solution 1:
The issue is caused by a mismatch between the WordPress database version and the version defined in your settings. To fix it, follow these steps:

• Open the file /wp-includes/version.php.
• Locate the value of $wp_db_version and make a note of it.
• Open your database and check the wp_options table.
• Find the db_version value:

SELECT option_value FROM yourdatabase.wp_options WHERE option_name = 'db_version';

• Ensure both values match. If needed, update the value in version.php — do not change the database value.

Solution 2:
Restarting the PHP-FPM service can help, as it clears the PHP cache.

Run the following command:

sudo service php5-fpm restart

This resolved the issue in my case and may help others experiencing similar problems.

Solution 3:
Try clearing your browser cache first.

If the db_upgraded option isn’t being set by the upgrade process, you can fix it manually:

• Go to /wp-admin/options.php.
• Locate the field db_upgraded and set its value to 0.
• Click Save Changes.

This should allow the upgrade process to complete correctly.