# Install app from the repository of a different version

Need mlterm 3.8.4-1 installed on a Lubuntu 16.04, which can only see version 3.5.0-1 of mlterm from the repository of Xenial Xerux. Is there any way to (say) target the repository of Bionic Beaver from the 16.04 version? I know, mlterm can be installed separately, but it's a question of including the dependencies in a deb file and install all necessary packages from there (there are packages no longer in the repository of version 18.04, that's way I'm staying in version 16.04).

• Not safely, because the dependencies for 16.04 and 18.04 probably differ substantially by the versions of libraries on the specific Ubuntu version that package was built for. You could cause package instability or program instability trying to mix an 18.04 repository's data with a 16.04 OS. – Thomas Ward Aug 9 '18 at 14:16
• @ThomasWard I guess it will be the same when trying to do the other way around: accessing from 18.04 some packages of the repository of 16.04. Correct? Just out of curiosity, how it is done? I mean, how to "redirect" to the other version's repository? – nightcod3r Aug 9 '18 at 14:20
• The problem of library incompatibility can arise, yes, with older software on newer versions of libraries. Basically, instead of xenial in the /etc/apt/source.list.d/ .list file for the specific repository, you replace that with 18.04's bionic (or vice versa for 16.04 repos on 18.04). The problem there though is you can run into uninstallability or version conflicts of libraries, or any number of issues that could result in system instability. – Thomas Ward Aug 9 '18 at 14:22
• @ThomasWard Understood. (By chance, may we be talking of configuration file /etc/apt/sources.list instead?) – nightcod3r Aug 9 '18 at 14:38
• it depends on how you add the repo, it'll either be an /etc/apt/sources.list entry or an entry in a specific .list file in /etc/apt/sources.list.d/. – Thomas Ward Aug 9 '18 at 14:53