The compatibility target is komga 1.27.1: the Flyway migrations, the OpenAPI document, and the behavior fixtures are taken from that release, and API behavior is ported from it. Improvements and intentional behavior differences are listed under Enhancements; accepted gaps under Known limitations.
Differential test harness
tests/diff/diff.py starts the Java komga and kmrs side by side over the same fixture library and compares ~105 endpoints (status, normalized JSON/XML bodies, headers, zip structure):
python3 tests/diff/diff.py --java-jar /path/to/komga.jar --rust-bin ./target/debug/kmrs