Tailscale releases a stable version regularly. Unstable versions are ahead of new releases for testing new clients.
Tailscale uses semver versioning.
Tailscale follows an alternating version numbering scheme. Even numbers (1.0, 1.2, 1.4) are stable versions, and odd numbers (1.1, 1.3, 1.5) are unstable versions.
Software always has bugs. For bug fixes, we deliver patches in the current stable version as well as the current (unstable) version, so that the bug fix lands in the next stable version release.
Tailscale aims to release a new stable version every 6 weeks.