which of the two it is?

3 Answers 3


Actually it depends. For LTS releases Ubuntu syncs with Debian Testing. For non-LTS releases, Ubuntu syncs with Debian Unstable.

  • +1 @OP: I think the syncing from testing for Lucid was an experiment. Remember that some packages (those that are maintained separately from Debian) aren't synced from Debian at all.
    – Umang
    Aug 5, 2010 at 14:58
  • 1
    Source? It looks like it is no longer the case for LTS releases: wiki.ubuntu.com/DebianImportFreeze
    – baptx
    Jan 25, 2019 at 9:49


In every Ubuntu release, there's an initial import from Debian unstable for many packages in main. After 9 weeks or so, that process is frozen and the versions are locked down.

However, there is still tracking done by the MOTU team for universe. Many packages come across from testing. (Many packages are also wholly original too.)

For both sets of packages, bug tracking is done on Launchpad and custom patches will be introduced or backported from the previous Ubuntu release.


Neither, but it resembles Unstable more of the two.

Ubuntu syncs packages during the development cycle from unstable and those packages then get stabilized and/or modified before release. At the time of the release, Ubuntu has fallen behind of Unstable quite a bit, but it adds time to find and fix the bugs that have crept in.

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