Such maintainer script should perform the upgrade as recommended by MySQL developers, so stepping one version a time; so, upgrading for example, from Ubuntu 14 to 16, it should upgrade MySQL 5.5 to 5.6, then 5.6 to 5.7.
Such maintainer script should perform the upgrade as recommended by MySQL developers, so stepping one version a time; so, upgrading for example, from Ubuntu 14 to 16, it should upgrade MySQL 5.5 to 5.6, then 5.6 to 5.7.