MySQL 5.7 Reference Manual
MySQL 5.7 Release Notes
Upgrade is only supported between General Availability (GA) releases.
Upgrade from MySQL 5.6 to 5.7 is supported. Upgrading to the latest release is recommended before upgrading to the next version. For example, upgrade to the latest MySQL 5.6 release before upgrading to MySQL 5.7.
Upgrade that skips versions is not supported. For example, upgrading directly from MySQL 5.5 to 5.7 is not supported.
Upgrade within a release series is supported. For example, upgrading from MySQL 5.7.
xto 5.7.yis supported. Skipping a release is also supported. For example, upgrading from MySQL 5.7.xto 5.7.zis supported.