We often update the manual at the same time we make changes to MySQL Workbench. If you find a recent version of MySQL Workbench listed here that you cannot find on our download page (http://dev.mysql.com/downloads/), it means that the version has not yet been released.
The manual included in the source and binary distributions may not be fully accurate when it comes to the release changelog entries, because the integration of the manual happens at build time. For the most up-to-date release changelog, please refer to the online version instead.
MySQL Workbench release notes are not published in the MySQL Workbench Manual.
Release notes for the changes in each release of MySQL Workbench are located at MySQL Workbench Release Notes.