It means the public API is not promised to be stable. The semantic versioning specification says anything may change at any time in version 0.y.z. Treat every minor bump of a 0.x SDK like a major one, and pin it tightly.
What the specification says
The Semantic Versioning 2.0.0 text reserves major version zero for initial development. Anything MAY change at any time, and the public API SHOULD NOT be considered stable. Version 1.0.0 defines the public API, and from then on the increments carry meaning: major for incompatible changes, minor for backward compatible additions, patch for backward compatible fixes.
Many authors use the minor number in 0.x the way others use the major number. That is common, but it is a habit, not a rule. A 0.x vendor may break you in a patch release and still follow the spec.
How range operators treat 0.x
The node-semver documentation describes the caret range as allowing changes that do not modify the left most non zero element. In practice:
| Range | Allows |
|---|---|
| ^1.2.3 | Minor and patch updates, up to but not including 2.0.0 |
| ^0.2.5 | Patch updates only, not 0.3.0 |
| ^0.0.4 | No updates |
So a caret range already protects you from the 0.2 to 0.3 jump. But look at what that implies. If your SDK is at 0.2.5, the tool treats 0.2.6 as safe to take automatically, and the spec makes no promise that it is.
For more on range operators see caret versus tilde version ranges.
Why it matters for deprecation risk
A 0.x SDK often has no deprecation policy, no long term support line and a small team. Features can disappear without a deprecation cycle. Three consequences follow.
- Upgrades need more testing per step, not less.
- The vendor may not backport security fixes to the 0.x version you run. You move or you stay exposed.
- A move to 1.0 may be a large change, since it is where the API gets defined.
What to do
- Pin exact versions for 0.x SDKs in your manifest and keep a lockfile, so no upgrade arrives unseen.
- Put the SDK in a higher review tier, with the register noting the version is pre 1.0.
- Read the changelog for every release, including patches.
- Isolate the SDK behind a thin wrapper, so a breaking change touches one file. See should you wrap a mobile SDK behind your own interface.
- Ask the vendor what their path to 1.0 looks like and how long they support older versions.
- If the SDK is on a critical path and the vendor will not commit to anything, plan a replacement.
Is 0.x always bad?
No. Plenty of reliable libraries stay on 0.x for years. The point is that the version number carries no guarantee, so you replace the guarantee with your own controls: pinning, testing and a wrapper.
Where Safeguard fits
Safeguard's dependency scanning and SBOM output list the exact version of every dependency, which lets you filter for pre 1.0 packages in your inventory. A free scan is at gold.safeguard.sh/scan.
Quick check
Is a patch release of a 0.x SDK safe to auto update?
Not by the specification. Anything may change in 0.y.z. Read the changelog and test before taking it.
Does a caret range keep me on 0.2.x if I declare ^0.2.5?
Yes. It allows patch updates only, so 0.3.0 is excluded.
Sources
- Semantic Versioning 2.0.0: https://semver.org/
- node-semver README, Caret Ranges: https://github.com/npm/node-semver/blob/main/README.md
- npm Docs, About semantic versioning: https://docs.npmjs.com/about-semantic-versioning
Last reviewed: 19 October 2026.
