> Major version zero (0.y.z) is for initial development. Anything MAY change at any time. The public API SHOULD NOT be considered stable.
> Version 1.0.0 defines the public API. The way in which the version number is incremented after this release is dependent on this public API and how it changes.
> If your software is being used in production, it should probably already be 1.0.0.
Basically, nobody wants to deal with backcompat. Having worked somewhere where we supported stuff more than a decade old, it's not entirely surprising. It's really hard to know what crazy stuff customers are doing with your stuff, and fun new things often die off during the pitch.
https://semver.org/
> Major version zero (0.y.z) is for initial development. Anything MAY change at any time. The public API SHOULD NOT be considered stable.
> Version 1.0.0 defines the public API. The way in which the version number is incremented after this release is dependent on this public API and how it changes.
> If your software is being used in production, it should probably already be 1.0.0.