I'd thought to upgrade from Ubuntu 16.04.4 to 16.04.5 you needed to run "sudo apt-get dist-upgrade".

I just ran

sudo apt-get update  
sudo apt-get upgrade 

and that took me from 16.04.4 to 16.04.5 after a reboot. "history" shows I've never run dist-upgrade.

Did I just misunderstand update+upgrade, paint myself into this corner some other way, and can I down rev back to 16.04.4 ?

Edit to add info: This is the server for a SW team, all of whom are supposed to be on the same revision of tools/compilers/op-system/etc. We're doing embedded development. All of us staying on the current rev is a big deal, so an accidental up-rev is ergo a big deal.

Now if this was expected behavior and it's not a serious upgrade then maybe I can just tell the team and have everyone else upgrade, but it seems like this shouldn't have happened.

Edit again: I meant 16.04.04 -> 16.04.05 NOT 14.04 (My apologizes)

I think this is related to unattended-upgrades

cd /etc/apt/apt.conf.d  

more 20auto-upgrades
APT::Periodic::Update-Package-Lists "1";
APT::Periodic::Unattended-Upgrade "1";

more 50unattended-upgrades
// Automatically upgrade packages from these (origin:archive) pairs
Unattended-Upgrade::Allowed-Origins {
    // Extended Security Maintenance; doesn't necessarily exist for
    // every release and this system may not have it installed, but if
    // available, the policy for updates is such that unattended-upgrades
    // should also install from here by default.
//  "${distro_id}:${distro_codename}-updates";
//  "${distro_id}:${distro_codename}-proposed";
//  "${distro_id}:${distro_codename}-backports";

I also think deleting 20auto-upgrades would prevent rev changes.

  • Welcome to AskUbuntu! Any particular reason why you want to go back? Is there anything that doesn't work any more? If so please specify in your question. Please keep in mind that the upgrade from to is nothing major, just bugfixes and small changes. Sep 6, 2018 at 19:26
  • It's a server for a SW team who are all supposed to be doing development on the same version of op-system/tools/etc. @MrShunz Sep 6, 2018 at 19:29
  • 1
    Well, a system should be kept upgraded, and since nothing major should change between minor versions, I suggest you bring all development servers to the version. Sep 6, 2018 at 19:39
  • @mrshunz So was this expected behavior? Sep 6, 2018 at 19:41
  • 1
    Have you run sudo apt-get dist-upgrade at all? The two other commands do not replace it.
    – zx485
    Sep 6, 2018 at 19:45

1 Answer 1


dist-upgrade is irrelevant to a point release, your system gets this just through regular updates. The ".x" will update when a certain small package called base-files is released through the regular update system.

If you look in your /var/log/apt logfiles for the day that your system changed to .5, you will find that this package got installed.

Here are comments on a point release from the official Ubuntu blog (emphasis mine)

If you’re already running 18.04 LTS, and you have been updating regularly, then you will already have all of these applied and so essentially you’re already running 18.04.1 LTS. The point release is an opportunity for us to make a new ISO image, and so people downloading and installing from the release of the new images will benefit from having those updates available immediately.

For more information about what dist-upgrade is, read the accepted answer to this question. TL;dr, dist-upgrade does not upgrade your system to a new release, it is merely a version of upgrade that is allowed to remove packages to resolve conflicts.

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