[conspire] How to update packages when Deb is behind?

[Rick Moen]

Quoting Paul Zander (paulz at ieee.org):

> I just looked up more than 20 different apps.   The versions
> installed, in Stretch and in Buster.  In some cases they are all the
> same.  In some cases the installed is a little older.
> 
> BUT there were a few "more interesting".  For example, GIMP.  The
> installed version is the same as testing and newer than stable.   The
> file date on /usr/bin/gimp is March 28.  That might have been the last
> time I did an `apt-get update`

As a reminder (and you probably are aware of this), 'apt-get update'
doesn't change installed software in any way.  It _just_ fetches a new
set of catalogues from all the listed apt sources, plunks them down into
/var/lib/apt/lists/* files, and then merges those to composite file 
/var/lib/dpkg/available (along with a hashed-index binary variant 
copy it stores somewhere else, that is the primary copy used by default
for speed purposes).

Here's the core of my lingering concern, about your converging attempt
that you hope will get you onto the current Debian-Stable track instead
of remaining a rather weird and out-of-date installation of some prior
date's Debian-Testing:  Consider the GIMP package (which is indeed
called 'gimp').  You say it's newer than the version currently in
Stable.  All well and good, not harmful, but what about the package's
dependencies?

Checking at p.d.o., dependencies include a boatload of GTK library
packages, plus some really deeply important system libs such as 

 libc6: GNU C Library: Shared libraries
 libxt6: X11 toolkit intrinsics library
 libx11-6: X11 client-side library
 libxext6: X11 miscellaneous extension library
 libxcursor1: X cursor management library
 zlib1g: compression library - runtime

That's some of the highlights, and there's a lot more you can see at
https://packages.debian.org/stretch/gimp for the current package
available in Stable.  And nota bene that the _versions_ of each
package dependency are given (that would get pulled in).

You say your installed GIMP is a later version than that.  OK, then,
does that mean it might have already pulled in a later libc6 package
than is standard in current Debian-Stable?  If so, when you try to
converge onto Debian-Stable using source.list adjustments and the
apt-get dance, what results may be not _exactly_ Debian stable but a
minor sort of Frankendebian, where some installed versions, including
those of vital packages like libc6, are post-Stable packagings.

As I was saying upthread, there's no harm in _trying_ to converge onto
current Debian-stable.  At worst, the outcome may end up glitchy such
that you decide to change tactics and converge a second time onto
current Debian-Testing, instead.  My point is merely that you should 
be prepared for the possibility.  As I said, Debian really does _not_
support package downgrading.   It can be done, but requires some
determination and work.



> The real outlier is Firefox.  I  Installed       stable|stretch  
> testing|buster  45.8               52.8.1             52.8.1


Are you saying the package name is 'firefox', and not 'firefox-esr'?
If so, that points, if a bit vaguely, to the nature of your problem.

I'm not aware of there having been in the past couple of years any
package within the main Debian branches (stable track, testing track, or
unstable track) called just 'firefox'.  Maybe there was one briefly, but
then it was removed from the archive and replaced with the current
firefox-esr package?  Not sure.  As I think I mentioned upthread, it's 
a potentially interesting and unresolved question as to where and how 
you came by that package.

> My present guess is that my sources.list file really was doing "testing", but something is amiss with Firefox. I know I have downloaded and added SeaMonkey without using apt-get.
> Possible fix: 
> #apt-get update
> #apt-get remove firefox#apt-get install firefox

Before you do anything, make sure you know the package name!
'dpkg -l | grep firefox'

And, to say it again, and maybe again, and again:  The packagae you
_want_ is firefox-esr.