COMPATIBILITY_NOTES_5.1.1

Compatibility Notes — Moira 5.1.1

Date: 2026-07-22

This patch release is backward compatible with 5.1.0 and changes only the reader-bound historical Delta-T admission for content-identified DE440/LE440 kernels.

Corrected behavior

Before the 1972 atomic-clock boundary, a DE440-backed chart no longer fails because the kernel identity lacks an admitted lunar tidal acceleration. The engine now binds DE440/LE440 to -25.936 arcsec/cy² and performs the same explicit historical source-basis translation already used for admitted reader-backed products.

No caller flag or migration is required. Existing chart, position, house, and REST request shapes are unchanged.

Preserved boundaries

• Kernel identity still comes from SPK summary content, not the filename.
• Unknown or unadmitted DE/LE identities still fail closed for basis-sensitive historical Delta-T products.
• Modern direct-EOP epochs do not receive a tidal-basis correction.
• DE430/LE430 remains admitted at -25.85 arcsec/cy².
• DE441/LE441 remains admitted at -25.936 arcsec/cy².

Upgrade action

Replace any installation-local DE440 hot patch with the published moira-astro==5.1.1 wheel. Services that import Moira must be restarted after the package upgrade so all processes load the canonical mapping from the released package.