docs/MIGRATION.md

Migration from EVE-CKLPO v1

Install celestis-rl v2.0.0 and change from eve_cklpo ... to from celestis_rl .... Both packages can exist separately, but the release does not install an alias that silently intercepts the old namespace. No remote repository is renamed or modified automatically.

TrainConfig now defaults to mode='stratified_safe'. To reproduce the v1 safe route explicitly, set mode='safe'; the original IID, trace and full routes also remain. run_tiny_lm defaults to recomputed selected backward; set head_backend='legacy' for the retained selected-head comparator. Use head_backend='exact_streaming' for an exact full-q correction without wasting sampled auxiliary draws.

Moment replay is opt-in through moment_sequence_loss/run_moment_lm, not an automatic replacement for arbitrary old q records. Construct the immutable feature bank first, capture moments from the actual old q while it is still available, and retain original contexts/rewards. A trainable tied vocabulary basis cannot be used as a frozen bank. New vocabulary directions cannot be recovered from discarded q. Exact affine bank changes may use AffineBankTransport.

Old checkpoint metadata and hashes are intentionally not silently rewritten by loaders. Historical evidence and its v1 checkpoints are segregated in results/inherited_eve_cklpo/; use the original v1 package to load them under its original contract. Current runnable v2 checkpoints are in results/celestis_v2/. load_moment_model restores the adapter-aware model forward path; load_tiny_weights restores the unrestricted-head token demo. Neither is a full optimizer/RNG training resume checkpoint.

Never reset the confidence ledger during a model migration or rollback. A changed policy is a new candidate audit with fresh paired evaluations; resuming the same audit is only valid while the candidate remains fixed. New concurrent/distributed use needs external locking rather than reusing single-process JSON persistence.