I'm writing a script which uses the output of
apt list --installed to install the same package version on a fresh VM install of (un-upgraded) 16.04.
The purpose is to test upgrade procedures, by creating a VM that is in the same "package-state" as a remote server (which suffers limited connectivity).
Some packages, such as
apache2-bin=2.4.18-2ubuntu3.10 are not installable because they are no longer in the main repos.
Where can discontinued packages be downloaded from?