Re: Discussion about why GNU/Linux system upgrades cause old programs to break

As far as I know, Linux distributions typically only guarantee the
functioning of the current set of packages they provide. This means that
the packages the distribution provides form a coherent whole where every
dependency is satisfied, but this guarantee does not extend to third-party
software packages, or even older versions of some official package, e.g.
Emacs. When a new version of Emacs is adopted by the distribution, the
older version is dropped on the assumption that the new Emacs version is a
total replacement for all the older versions. If some dependency of the old
package is not needed anymore it is dropped, unless it is still needed by
some other package.

This means a traditional distribution-based Linux installation is not very
friendly to people who are developing their own software, building third
party software, or trying to run an older version of a packaged
application. When going outside the boundaries of pre-packaged apps, the
burden to keep the apps running is on the user, not the distribution
provider. This may require rebuilding and installing compatible versions of
libraries (in e.g. /usr/local/lib). I'm not sure there even exists a
concept of "system libraries" on Linux. Glibc would definitely be
considered a system library, but I'm not sure if GTK 2.0 fits into that
category. The list of "system libraries" and their versions would
definitely be different depending on which distro maker you ask.