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specify the MySQL root  user. Commands that require a password for root  also include a -p  option. Because -p  is followed by no option value, such commands prompt for the password. Type the password when prompted and press Enter. 

SQL statements can be executed using the mysql  command-line client (connect as root  to ensure that you have the necessary privileges). 

## 2.11.1 Before You Begin 

Review the information in this section before upgrading. Perform any recommended actions. 

•Understand what may occur during an upgrade. See Section 2.11.3, “What the MySQL Upgrade Process Upgrades” . 

•Protect your data by creating a backup. The backup should include the mysql  system database, which contains the MySQL data dictionary tables and system tables. See Section 7.2, “Database Backup Methods” . 

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## Important 

Downgrade from MySQL 8.0 to MySQL 5.7, or from a MySQL 8.0 release to a previous MySQL 8.0 release, is not supported. The only supported alternative is to restore a backup taken before  upgrading. It is therefore imperative that you back up your data before starting the upgrade process. 

•Review Section 2.11.2, “Upgrade Paths”  to ensure that your intended upgrade path is supported. 

•Review Section 2.11.4, “Changes in MySQL 8.0”  for changes that you should be aware of before upgrading. Some changes may require action. 

•Review Section 1.3, “What Is New in MySQL 8.0”  for deprecated and removed features. An upgrade may require changes with respect to those features if you use any of them. 

•Review Section 1.4, “Server and Status Variables and Options Added, Deprecated, or Removed in MySQL 8.0” . If you use deprecated or removed variables, an upgrade may require configuration changes. 

•Review the Release Notes for information about fixes, changes, and new features. 

•If you use replication, review Section 17.5.3, “Upgrading a Replication Setup” . 

•Upgrade procedures vary by platform and how the initial installation was performed. Use the procedure that applies to your current MySQL installation: 

•For binary and package-based installations on non-Windows platforms, refer to Section 2.11.6, “Upgrading MySQL Binary or Package-based Installations on Unix/Linux” . 

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## Note 

For supported Linux distributions, the preferred method for upgrading package- based installations is to use the MySQL software repositories (MySQL Yum Repository, MySQL APT Repository, and MySQL SLES Repository). 

•For installations on an Enterprise Linux platform or Fedora using the MySQL Yum Repository, refer to Section 2.11.7, “Upgrading MySQL with the MySQL Yum Repository” . 

•For installations on Ubuntu using the MySQL APT repository, refer to Section 2.11.8, “Upgrading MySQL with the MySQL APT Repository” . 

