Upgrading to 0.3

Back up first

Opening a 0.2 database upgrades metadata.db to a new file format, after which 0.2 can no longer open it. Copy the database directory before upgrading.

Change	What to do
Python 3.9+ required	Upgrade Python 3.8 environments.
numpy, psutil, scikit-learn no longer installed	Add them to your own dependencies if you import them.
Class renamed to srvdb.Database	srvdb.SrvDBPython still works with a warning until 0.4.
Scores are true cosine in [-1, 1] (were (1 + cos) / 2 for flat, HNSW, IVF)	Convert thresholds: new = 2 × old − 1. Order is unchanged.
Metadata must be a JSON object	Wrap plain strings: {"text": "..."}.
Specific exceptions	Catch ValueError / OSError / BlockingIOError instead of only RuntimeError.
One open instance per database	Share one Database between threads.
persist() is the commit point	Later writes are discarded after a crash; persist at checkpoints.
count() excludes deleted vectors	—
Auto mode never compresses	Open with mode="sq8" if you relied on it.
Licence is Apache-2.0 (was AGPL-3.0)	Nothing; you have more freedom.

Full list: CHANGELOG.