Updates

An installed copy of Kontena keeps itself current. It checks for a new version when it starts, fetches it in the background, and waits for you to restart. Nothing is applied behind your back, and your containers keep running — only the app restarts.

What you will see#

A new version announces itself once with a toast. After that it waits as an entry at the bottom of the sidebar, which follows along rather than repeating itself. Click either one to open the update card.

The card shows the version on offer, its download size and the release notes that came with the package, so you can read what changed before deciding.

A version you wave away keeps its sidebar entry but does not toast at you again — it is there when you want it, and quiet until then.

Channels#

Settings › Updates picks which builds Kontena offers you:

• Stable — tagged releases only. This is the one to be on unless you are testing Kontena itself.
• Preview — built from main: what has been promoted for the next release, before it is tagged. Ahead of stable, past the roughest edges of nightly.
• Nightly — cut from develop every night: everything that is finished, and whatever came with it. The first place a regression shows up.

Switching channels re-checks immediately, because what was found on the old feed no longer applies.

A rolling build follows its own channel#

Download a nightly or a preview and start it without an existing configuration, and Kontena follows that channel — you do not have to configure anything to keep getting what you deliberately downloaded. Settings says so while nothing has been picked: "This is a nightly build, so Kontena is following that channel. Pick one to decide for yourself."

A channel you pick yourself always wins, and an install never drifts onto a rolling stream on its own. Existing installs keep whatever channel they already had, so updating never changes what you are offered next.

Downloading in the background#

Download updates automatically is on by default: a new version is fetched as soon as it is found, so the update is a restart rather than a wait. Turn it off — on a metered connection, say — and Kontena still tells you a version exists, but only downloads it when you press the button.

Check now, on the same page, checks on demand and reports being up to date, which the check on launch deliberately does not.

When Kontena cannot update itself#

Not every install is one the updater owns. Run Kontena from an unpacked archive, from a build directory, or from a package your distribution installed, and it says so rather than offering a button that would do nothing:

That is a normal way to run Kontena, not an error. Updating by hand is the same as installing:

Your settings, engines, clusters and remembered choices live outside the application folder, so replacing the app by hand does not disturb them.

When an update fails#

A failed check or download is recoverable, and the card says what went wrong in the words it got back. Try again retries; the sidebar entry survives a dismissed failure card, so you are never left without a way back to it.

If it keeps failing, the usual causes are the ordinary ones: no route to GitHub, a proxy or firewall in the way, or an install the updater cannot write to. Downloading the new version from the releases page and installing it by hand always works and is not a workaround — it is the same package the updater would have fetched.

Going back to an older version#

There is no in-app downgrade: the updater only ever moves forward. To go back, download that version's installer from the releases page and run it. Then pick the matching channel in Settings › Updates, or the next check will offer you the newer build straight back.

What changed#

The card shows the notes for the version it is offering. The full history is in CHANGELOG.md, and every release carries the same notes on its release page.

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