Versions & Releases¶
Major, Minor, or Patch¶
Since the 1.0.0 release, Syncthing uses a semver-like 1 three part version number, x.y.z where x is the major version, y is the minor version, and z is the patch version. We decide the version number for a new release based on the following criteria:
Is the new version protocol incompatible with the previous one, so that they cannot connect to each other or otherwise can’t sync files for some reason? That’s a new major version. (This hasn’t happened yet.)
Are there changes in the REST API so that integrations or wrappers need changes, or did the database schema or configuration change so that a downgrade might be problematic? That’s a new minor version.
If there are no specific concerns as above, it’s a new patch version.
There are two different release channels that can be selected. The stable channel is the more stable one, while candidate releases are closer to development. Candidate releases get promoted to stable after a certain period of testing.
There are a few trade-offs between the two:
Features & Fixes
One month behind
Anon. Usage Reporting
Fully supported 3
Run the candidate channel if you are technically savvy and enjoy new features. Run the stable channel if you want to minimize the amount of surprises you might run into.
Auto upgrades are not enabled in builds delivered via APT.
Yes, there is intentionally no difference here.
Barring blocking issues, stable versions are released on the first Tuesday of the month. A new candidate releases is made on the second Tuesday of the month.
How to Choose¶
Built-in / GitHub¶
For releases obtained from Syncthing.net or GitHub, with built-in upgrade functionality, the choice is made in the “Settings” dialog. Set the “Automatic upgrade” drop down to either “Stable releases only” or “Stable releases and release candidates”.
The choice between stable and candidate is done in the APT source configuration. Please see our APT instructions.
Docker images are pushed to several tags. By pulling a specific tag you can select the release channel you want:
syncthing/syncthing:latestpoints to the latest stable release, e.g.
syncthing/syncthing:rcpoints to the latest release candidate, e.g.
syncthing/syncthing:nightlypoints to the latest nightly development build, e.g.
There are also tags for the major and minor versions, for example
syncthing/syncthing:1.9 for the latest stable 1.9 patch release and
syncthing/syncthing:1 for the latest stable release with major version
Some Other Distribution Channel¶
If you are getting packages from your Linux distribution, NAS vendor, etc., then you should be getting the stable channel. If you get a release candidate you should complain to your distributor or vendor and refer them to this page.
It’s also possible to run the nightly development builds. These are not
releases in any sense of the word, they are simply builds of the current
main branch of the repository. These builds are not supported and may
contain functionality that is changed or removed before the actual release.
To use nightly releases, in Advanced Settings -> Options,
Change “Releases URL” to
Enable “Upgrade To Pre Releases”
Restart Syncthing and it will upgrade to the latest nightly. New nightlies are published at midnight UTC.
What’s the relationship between candidate and release exactly?¶
Every new feature and bugfix begins its life in the development branch,
main. Once a month the current
main becomes a release
candidate. This version is identified by “-rc” in its name, for example
Those running the candidate channel will update to this release candidate.
For the next three weeks it is tested “in the wild”. Any new, serious issues
that are discovered are fixed, and new release candidates
are created as needed. These release candidates do not include any new
features or non-essential bugfixes added to
main in the meantime.
Stable releases are given version numbers without any suffix -
Unless any serious issues were discovered, this release is exactly identical
to the “-rc.1” release candidate three weeks prior.
The cycle then restarts one week later with a new release candidate based on
Which bugfixes trigger a new release candidate?¶
Those that fix a regression since the last release. Lets say the current
v1.5.0. We release
v1.5.1-rc.1 and discover a new problem that
is not present in
v1.5.0. This gets fixed and we release a new
candidate. However, if we discover and fix a problem that’s been present
v1.4.0, this fix will instead be incorporated in the next regular
What’s the difference between the latest candidate and the following stable release?¶
Nothing. If we release
v1.5.1-rc.1 and no serious problems are discovered
during the next twelve days, this is the exact software that will become
v1.5.1 for general consumption. Since the version number is different it
requires a rebuild and the release signatures / hashes are different. If you
are on the candidate channel, your Syncthing will “upgrade” from
v1.5.1 when we make the release. This is normal.
SemVer-like because semver is absolutist about what constitutes an API change, in a way that isn’t super helpful to the average user of a program like Syncthing.