Co-op netcode v2 and the fast UDP relay

Co-op used to feel laggy for guests, and it wasn't your internet. Your own hero waited a full round trip before moving, and everyone else updated ten times a second with a jump.

Netcode v2

• Your hero moves the instant you do (prediction); the leader's game quietly corrects you if you disagree.
• Everyone else is smoothed between snapshots (interpolation) with a small jitter buffer, so they glide instead of teleporting.
• Snapshots are binary and only carry what changed since the last one you confirmed: a fraction of the old size, 20 times a second.

The fast path

• Party games now travel over a UDP relay (Cloudflare's TURN network) when it connects. A lost packet no longer stalls everything behind it.
• Relay only: players never see each other's IP addresses. Traffic always goes player → Cloudflare → player.
• If the fast path can't connect, the game drops back to the classic relay on the very next frame. Settings → Network lets you pick Classic relay only.