Bug#941952: linux-headers-3.16.0-6-amd64 package removed from stable repository

[Javier López <jalopez@tripwire.com>]

Package: linux-headers-3.16.0-6-amd64
Version: 3.16.56-1+deb8u1
Severity: normal

Dear Maintainer,

I work for a security focused company and part of my work is to check our DKMS
modules are well supported in Debian, recently I've started to have issues with
the linux-headers-$(uname -r) packages in Debian 8/9, it seems as the kernel
gets updates new linux-headers (linux-image) packages are generated and the
previous ones are removed from the stable repositories, I can workaround this
problem by adding the snapshot repositories, however I'm unsure if this is the
normal behavour in Debian, is there any formal document that states clearly how
these kernel updates are handled to stable users?

At the moment of writing this I'm on a Debian 8.10 system where the running kernel
is: uname -r 3.16.0-4-amd64 which has no matching headers
apt-get install linux-headers-$(uname -r)

Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package linux-headers-3.16.0-4-amd64
E: Couldn't find any package by regex 'linux-headers-3.16.0-4-amd64'

The system have more update kernel packages:

$ apt-cache search linux-headers- | grep 3.16
linux-headers-3.16.0-6-all - All header files for Linux 3.16 (meta-package)
linux-headers-3.16.0-6-all-amd64 - All header files for Linux 3.16 (meta-package)
linux-headers-3.16.0-6-amd64 - Header files for Linux 3.16.0-6-amd64
linux-headers-3.16.0-6-common - Common header files for Linux 3.16.0-6
linux-headers-3.16.0-10-all - All header files for Linux 3.16 (meta-package)
linux-headers-3.16.0-10-all-amd64 - All header files for Linux 3.16 (meta-package)
linux-headers-3.16.0-10-amd64 - Header files for Linux 3.16.0-10-amd64
linux-headers-3.16.0-10-common - Common header files for Linux 3.16.0-10

-- System Information:
Debian Release: 8.10
  APT prefers oldoldstable
  APT policy: (500, 'oldoldstable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.utf8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages linux-headers-3.16.0-6-amd64 depends on:
ii  linux-compiler-gcc-4.9-x86     3.16.74-1
ii  linux-headers-3.16.0-6-common  3.16.56-1+deb8u1
ii  linux-kbuild-3.16              3.16.56-1

linux-headers-3.16.0-6-amd64 recommends no packages.

linux-headers-3.16.0-6-amd64 suggests no packages.

-- no debconf information