CompareVersions returns a relation describing how a compares to b.

FetchLatestReleases returns the latest releases.

Versions are semantically equal.

Newer by a major version (x in x.y.z or 0.x.y).

Older by a major version (x in x.y.z or 0.x.y).

Newer by a minor version (y or z in x.y.z, or y in 0.x.y).

Older by a minor version (y or z in x.y.z, or y in 0.x.y).

SigningKey is the public key used to verify signed upgrades.