This is the first MySQL Enterprise Server release, following the last Community Server release (5.0.27).
Binary MySQL distributions no longer include a mysqld-max server, except for RPM distributions. Instead, distributions contain a mysqld binary that includes the features previously included in the mysqld-max binary.
MySQL 5.0.26 introduced an ABI incompatibility, which this release reverts. Programs compiled against 5.0.26 are not compatible with any other version and must be recompiled. (Bug #23427)
InnoDB: Reduced optimization level for Windows 64 builds to handle possible memory overrun. (Bug #19424)