I cannot run apt-get update as I encounter the following error:

# apt-get update
Hit:1 http://ftp.br.debian.org/debian testing InRelease
Ign:2 http://security.debian.org/debian-security testing/updates InRelease
Err:3 http://security.debian.org/debian-security testing/updates Release
  404  Not Found [IP: 80]
Reading package lists... Done
E: The repository 'http://security.debian.org/debian-security testing/updates Release' no longer has a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Repository 'http://ftp.br.debian.org/debian testing InRelease' changed its 'Codename' value from 'buster' to 'bullseye'
N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.

So there are two error messages here:

  1. The repository no longer has a Release file, which is weird. I checked at http://security-cdn.debian.org/debian-security/zzz-dists/testing/updates/ ant it looks like the Release file is there. Am I looking in the wrong place or is there something else happening?
  2. The repository changed its name from buster to bullseye and that this "must be accepted explicitly" (I saw this once today; it wasn't there when I opened the question and it does not appear anymore). This isn't really surprising, but I didn't expect it to be a problem if I'm tracking the repository as testing instead of the release name.

What can I do? APT is telling me to read the apt-secure(8), but it either does not have the information I need or I cannot understand it.

4 Answers 4


Change testing/updates to testing-security in your sources.list to match http://security-cdn.debian.org/debian-security/dists/testing-security/

Then run apt update instead of apt-get update to interactively accept the various changes.

According to this reddit post this repository name change was introduced in release 10.

  • This answer seems to be the only one that answers the actual question, although the other answers are still interesting. Jul 9, 2019 at 22:50
  • 3
    I've wondered about apt vs apt-get for a long time now. This caused me to finally look it up. apt is the preferred way to do package management for end-users.
    – Phil
    Jul 12, 2019 at 5:03
  • This solves the issue. In addition, the answer to my other question is: the link I posted is correct; no Release file is missing. But the file says "buster". I'm guessing it was deprecated a while ago and I missed the announcement.
    – giusti
    Jul 15, 2019 at 1:52
  • 1
    The link you posted does exist indeed, but the zzz-dists part in the URL is unusual. It looks like a folder I would rename to push it down a file list. I wasn't aware of the testing/updates renaming until I faced the same issue as you did. It is mentioned by Debian: If you are tracking testing or the next-stable code name, you should always have a corresponding deb security.debian.org <"testing" or codename>-security main line in your /etc/apt/sources.list .
    – slv
    Jul 17, 2019 at 22:52
  • 1
    This is not what the various links posted say, nor what I have in place in my sources.list. So I checked and using testing-security/updates does not raise any kind of error. Hashing the corresponding files in /var/lib/apt/lists yields the same values, so there are multiple ways of collecting the same package list.
    – slv
    Apr 16, 2022 at 7:00

If you're upgrading from testing to buster, also be sure to run

apt-get update --allow-releaseinfo-change

If not, apt-get update won't let you update with Buster and will spit out messages like these:

N: Repository 'http://deb.debian.org/debian buster InRelease' changed its 'Version' value from '' to '10.0'

E: Repository 'http://deb.debian.org/debian buster InRelease' changed its 'Suite' value from 'testing' to 'stable'

N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.

N: Repository 'http://security.debian.org/debian-security buster/updates InRelease' changed its 'Version' value from '' to '10'

E: Repository 'http://security.debian.org/debian-security buster/updates InRelease' changed its 'Suite' value from 'testing' to 'stable' N: This must be accepted explicitly before updates for this repository can be applied. See apt-secure(8) manpage for details.


According to Debian Project News published 1st of July, Debian 10 "Buster" was scheduled to transition from testing to stable on 2019-07-06.

It looks like the transition was in fact performed as scheduled, and so the testing distribution should now be catching up witn unstable, to eventually become Debian 11 "Bullseye". You might be experiencing some temporary side effects because of this transition of the Debian mirrors.

If you want to stay with Debian 10 "Buster", now would be a good time to switch your /etc/apt/sources.list to use the release name buster instead of testing.

Otherwise, you'll soon be getting the raw bleeding-edge stuff from unstable, and you might accidentally get a partial upgrade to proto-"Bullseye".

Also, this is a reminder for anyone using the word stable in their /etc/apt/sources.list to consider whether to change it to stretch and stay with the old version, or read the Release Notes and perform the recommended upgrade steps.

  • 1
    What would I have to do if I want to keep using the Testing branch? What should my sources.list say? Thanks! Jul 7, 2019 at 17:19
  • 2
    Before 2019-07-06, testing meant Debian 10; now it means Debian 11. If you want to stay with Debian 10 you've been using so far, you should change the word testing in your sources.list to buster right now. On the other hand, if you actually want to be in the vanguard of the Debian 11 sprint, don't change anything. Perhaps wait a week or two for the worst of the storm to pass, monitor the appropriate Debian mailing lists, then run apt full-upgrade and see what happens. If something gets broken, make nice bug reports. You'll be testing Debian 11 while it starts to take shape!
    – telcoM
    Jul 7, 2019 at 17:48
  • PS: apparently there's something I missed in the error message yesterday or that's new. I'll check in the logs.
    – giusti
    Jul 7, 2019 at 22:10
  • 1
    Nope. This is definitely new. I was aware of the transition. In fact, this is why I attempted to upgrade yesterday. To the best of my knowledge testing just came out of freeze and I wanted to update. So what is APT telling me? How do I "explicitly accept" the new codename of the distribution? I don't remember ever doing this before.
    – giusti
    Jul 7, 2019 at 22:17
  • The codename of testing has changed from buster to bullseye to reflect the Debian 10 -> 11 transition, and that codename is included in the Release files. Looks like your version of apt is smart enough to block accidental upgrades from buster to bullseye. The priority of the Debian Project is likely in getting the new stable out and fixing any issues on it, so testing might be slightly broken for a few days until they get to creating the new APT keys for the new testing release. You may have to manually update the debian-archive-keyring pkg once a new one is released.
    – telcoM
    Jul 7, 2019 at 22:36

Run apt update and accept changes (type y each time when asked). It will made all required changes.

  • This works for those who want to remain with "buster release" which became stable.
    – Tony Power
    Jul 10, 2019 at 17:46

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