This is typically a decision between the latest stable release and
the latest development release. In general, we recommended that you
go with the latest stable release, unless you need specific features
in a development release that are not available in the stable
release.
The current stable versions are MySQL 3.23 and MySQL-Max 3.23.
MySQL-Max is a beta release of the MySQL software with support for
transactions (via BerkeleyDB and InnoDB tables). The standard MySQL
binary does not include support for these types of tables.
The current development versions are MySQL 4.0 and MySQL-Max 4.0. The
installation instructions provided here will work with either Version
3.23 or 4.0.