Tanto quanto eu sei, você deve ser capaz de usar as opções padrão com apt-get dist-upgrade para simular a execução deste comando sem realmente executar a atualização.
-s, --simulate, --just-print, --dry-run, --recon, --no-act
No action; perform a simulation of events that would occur but do not actually change the
system. Configuration Item: APT::Get::Simulate.
Simulate prints out a series of lines each one representing a dpkg operation, Configure (Conf),
Remove (Remv), Unpack (Inst). Square brackets indicate broken packages with and empty set of
square brackets meaning breaks that are of no consequence (rare).
-u, --show-upgraded
Show upgraded packages; Print out a list of all packages that are to be upgraded. Configuration
Item: APT::Get::Show-Upgraded.