Excuse me? That's a direct cut-and-paste from the apt-get man page. It is, but it only half-answers the question. The original discussion involved the difference between upgrade and dist-upgrade. The quote I cited implied that upgrade is safer than dist-upgrade because upgrade doesn't remove packages, while dist-upgrade may remove packages.
My comment pointed out that the apt-get man page entries for upgrade and dist-upgrade do not justify that implication: the only distinction the apt-get man page drawns between upgrade and dist-upgrade is between their abilities to resove conflicts. To fully answer the question, you have to also cut-and-paste the dist-upgrade entry in the apt-get man page and point out where it is written that dist-upgrade may delete packages. Then you can correctly conclude that upgrade is safer than dist-upgrade with respect to deleting packages. 'upgrade' is not allowed to change the installation state of a package, 'dist-upgrade' is. That may be true for apt-get (the apt-get man page entries for upgrade and dist-upgrade mention nothing about installation state), but it doesn't seem to be true for aptitude, where the man page suggests that upgrade may change an unused package state from installed to not-installed: Installed packages will not be removed unless they are unused -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]