Immersive Portals - CE 6.1.3

Minecraft 1.21.1 / NeoForge 21.1.228+ / Java 21

Fixed

• Evaluate Sable retained-rider approach at the authoritative mounted eye: the riding attachment plus the immediate passenger's eye offset, transformed by the native body pose. Previously, rolling or pitching could carry that eye inward through a static portal while the seat origin remained stationary or moved outward, causing the request to be rejected.

• Use that same point for native angular motion and source-portal motion, preserving rejection of outward, stationary, non-finite and stale approaches. Carry the immediate passenger correctly when traversing a nested mount graph.

• Prevent Sable UDP snapshots and interpolation-clock updates from being applied to the wrong dimension when packets interleave with a dimension change. Negotiate explicit dimension provenance while retaining native UDP between capable peers and legacy-wire redirected TCP for mixed-version peers; no user configuration changes.

Verification and limits

• Add numerical roll/pitch and opposite-direction regressions, compiled-production contracts for mount traversal and eye-point producers, and a native guard GameTest with real rigid-body velocities and direct/nested mounted entities.
• Add a deterministic two-world snapshot/clock interleaving probe, legacy-wire and mixed-peer policy contracts, and actual UDP/TCP transport receipts. See snapshot protocol and compatibility.
• The native GameTest exercises the production approach guard. It does not certify complete rolling-flight migration, packet ordering or rendering. Existing ship/network/renderer lanes remain unchanged and required; passing historical runs do not verify this new patch.
• Full moving-portal rotation/energy behavior, independently moving carts and unseated passengers remain outside the established coverage. Exact-head CI results belong in the pull request.

No release publication is implied by these notes.