0.4.6.1-1ubuntu1 from the gutsy repositories (
aptitude 0.4.6.1) has shown some changes. One of them is the replacement of
safe-upgrade Upgrades installed packages to their most recent version. Installed packages will not be removed unless they are unused (see the section “Managing Automatically Installed Packages” in the aptitude reference manual); packages which are not currently installed will not be installed. It is sometimes necessary to remove or install one package in order to upgrade another; this command is not able to upgrade packages in such situations. Use the full-upgrade command to upgrade as many packages as possible. full-upgrade Upgrades installed packages to their most recent version, removing or installing packages as necessary. This command is less conservative than safe-upgrade and thus more likely to perform unwanted actions. However, it is capable of upgrading packages that safe-upgrade cannot upgrade. Note This command was originally named dist-upgrade for historical reasons, and aptitude still recognizes dist-upgrade as a synonym for full-upgrade.
Please note that dist-upgrade will still work as usual, and that you will get this message when upgrading:
isabella@yeti:~ $ sudo aptitude upgrade [sudo] password for isabella: W: The "upgrade" command is deprecated; use "safe-upgrade" instead.