Receiver: a Mixed (plain) session is rendered on an active lane in BothIndependent mode instead of being skipped, so a WASAPI-only sender is no longer silent to a receiver that has an ASIO driver selected. Also port the per-session buffer depth-drain (stops the receive jitter buffer bloating).
Sender: add sndAudFr meter (audio frames actually sent) to localise capture vs send.
App: startup sound cue (machine-wide, Preferences); stop sending audio when no peer is reachable (issue #8). Version 3.9.1.
Server (relay): fix updater version-compare for multi-dot tags, guard the main loop against crashes, reject spoofed BYE from a mismatched endpoint.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>