That's a bad edit, and the text is not correct. It should read:
[begin]
MySQL 8.1 supports upgrades from previous versions of MySQL as specified here:
·Upgrades from MySQL 8.0 to 8.1 are supported between General Availability
(GA) releases only. For MySQL 8.1, it is required that you upgrade from a
MySQL 8.0 GA release (8.0.11 or higher). Upgrades from non-GA releases of
MySQL 8.0 are not supported.
·Upgrading to the latest release in the series is recommended before
upgrading to the next release series. For example, upgrade to the latest
MySQL 8.0 release before upgrading to MySQL 8.1.
·Upgrades that skip release series are not supported. For example, upgrading
directly from MySQL 5.7 to 8.1 is not supported.
[end]
We've made corrections which should be published in the online Manual soon.
Thanks for pointing out this issue to us.
cheers
Jon Stephens
MySQL Documentation Team @ Oracle
MySQL Dev Zone
MySQL Server Documentation
Oracle