Using (old) Ubuntu libjpeg packages to allow some older programs still running on recent debian

["Maris, Rob" <maris.rob@posteo.de>]

The subject is considered as dealing with Utnubu - but according to the appropriate wiki page, this team has stopped to exist "many years ago". Therefore I write in this list.

Next I describe a case which make me think that Debian has less a focus on keeping less recent lib packages part of more recent debian versions. More important: two other packages part of both Ubuntu and Debian prove to result in removal of old programs on Debian, but not on Ubuntu!

Regarding better backward compatibility: libjpeg8 and libpeg62 exists both in Ubuntu (till today); but in Debian only the latter. In my case I had to install libjpeg8 from ubuntu on my debian-based system (as well as gstreamer0.10-plugins-good)

Yesterday, I experienced that installation of jhead on a Debian based-machine results in installing just a slightly different version of libjpeg-turbo-progs and libturbojpeg0 (compared to Ubuntu). In my case this would also incur removals of libjpeg8 and libjpeg-turbo8 & gstreamer0.10-plugins-good, which I "imported" some time ago from Ubuntu packages in order to continue the use of old application stuff. Doing the same (installing jhead on an ubuntu-based machine) does not affect anything. But: when apt install jhead is executed on Debian 11 *after* the next two Ubuntu packages are installed via dpkg, no complaints are made.

To be precise:
   Debian                            |  Ubuntu
   libjpeg-turbo-progs 1:2.0.6-4     |  libjpeg-turbo-progs 2.0.6-0ubuntu2
   libturbojpeg0 1:2.0.6-4           |  libturbojpeg 2.0.6-0ubuntu2

Please take notice of the extra 0-suffix in the libturbojpeg name from the Debian 11 repository. My actual question: what does the Debian-version of these two libs make incompatible with libjpeg8 and three other libs - all "imported" from Ubuntu?

A practical problem arises with these two libs. When apt upgrade (or e.g. use KDE discovery) is being executed, the system will try to "upgrade" these two packages to the original Debian version. And that's annoying because I must decline those upgrades in order to prevent the automatic removal of four lib packages and one (old) application...

Regards,
Rob