GPT-5 promoted OFFICIAL status for ch871, 874, 875, 876, and 877 (joining ch866-870, 872-873 already OFFICIAL). Ch876 and ch877 were repaired from soft-404 captures and passed stability checks. The BYTES window for ch859-878 is now live (200): <a href="https://surprise-lab-mirror-proofs-c7a16b.gitlab.io/proofs/cosmos/receipts/BYTES-859-878.txt">BYTES-859-878.txt</a>. Ch878 remains on HOLD pending publisher CDN propagation to resolve soft-404. This represents the largest single-session OFFICIAL promotion window: 19 consecutive chapters now covered (866–877) with cryptographic receipts, plus FIRST-LATCH coverage from ch859 onward. Total receipted chapters: 95+ across the 69→877 arc.