Which version of Debian is Ubuntu 18.04 based on?

Question

Which version of Debian is Ubuntu 18.04 LTS based on? Assuming I do not have access to verify this on an existing Ubuntu 18.04 instance.

Solution

Used to be that LTS releases were based on -testing and "regular" releases were based on unstable (sid). Now however (started with 14.04), they are all based on unstable, exact versions, etc. of whatever packages will depend on when exactly Ubuntu pulls their snapshot.

Comments

[Admin]

How is this a duplicate? It is asking a very specific question that is not answered in the supposed duplicate question. The supposed previous answer assumes you are already running Ubuntu 18.04, which I am not.

[Admin]

The answer to the linked question explains why there is no single version of Debian upon which Ubuntu 18.04 is based. It also gives a way to find where a given Ubuntu release imported its packages from without having a running Ubuntu system (“you can also match Debian import freeze dates from the release schedules”).

[Admin]

@StephenKitt That is not the case. As mentioned in a comment below, you can clearly check the Debian version Ubuntu is based on by viewing /etc/debian_version. I was hoping that someone running Ubuntu 18.04 could check /etc/debian_version and answer this question. But unfortunately you were too fast at the trigger and incorrectly marked this question as a duplicate.

[Admin]

I’m not disputing the fact that there is a /etc/debian_version file in Ubuntu, I’m saying it doesn’t convey information that’s really meaningful. Ubuntu 18.04’s /etc/debian_version says buster/sid. Does that mean that 18.04 is based on Debian 10 (Buster), which we will release sometime next year? I’m pretty certain Canonical doesn’t have access to a time machine.

[Admin]

Take a specific example: Ubuntu 16.04, 16.10, 17.04 and 17.10 all have a debian_version which says stretch/sid. If that means they are all based on Debian 9 (Stretch), how come they all have different versions of libevdev, when that’s a pure Debian package with no Ubuntu changes? How can 16.04 have a version of that package which is older than the version in Debian 9, and yet still be based on Debian 9? How can 17.10 have a version newer than that in Debian 9?

[kemotep]

To build off of this answer you can check out these posts 1 2 for more information. @AJ. you should be able to check /etc/debian_version on your Ubuntu 18.04 Live Boot to see what version of Debian they pulled from.

[AJ.]

@kemotep Unfortunately I’m not yet running Ubuntu 18.04. Depending on the version of Debian it’s built on will determine if I will be running it or not.

[rbaleksandar]

@AJ If the determining factor whether you will be installing 18.04 or not is based on which version of Debian it is based on, perhaps you should consider moving to Debian in the first place. :)