Tailscale version mismatch causes false down alerts in monitoring

When tailscale CLI version differs from tailscaled daemon version (e.g., after package upgrade without daemon restart), the tailscale ping command outputs a version mismatch warning to stderr while successfully completing the ping. Monitoring systems that treat any stderr output as a failure condition will incorrectly report the service as down, even though the ping returns exit code 0 and a successful pong response.

After upgrading the Tailscale package, restart the tailscaled daemon to sync versions. For monitoring implementations: modify health checks to evaluate exit code (0 = success) or presence of 'pong' message in stdout instead of treating stderr output as a fatal error. Differentiate between warnings on stderr and actual ping failures.