v5.0.0

• There was some drift in the math used on the Python port which caused slight output drift relative to prior versions. It's small (~1e-8 per call) but this can compound over time. If you re-derive your ratings from the beginning of time, you might see an unbiased difference.
• Thurstone-Mosteller no longer uses gaussian; its Math.exp is only approximately specified by ECMAScript. It now uses CDF/PDF norm functions from stdlib, deterministic across platforms.
• preventSigmaIncrease was renamed to limitSigma in v4.0.0. The original has now been removed.
• sigma now defaults to 25/3 instead of being derived from mu/z.
• beta now defaults to 25/6 instead of being derived from mu/z.
• tau is now applied unconditionally (pass tau: 0 to disable); default changed from mu/300 to 25/300.
• epsilon (Thurstone-Mosteller draw margin) now defaults to 0.1 (was 0.0001). The per-step sigma floor is now keyed off kappa (default 0.0001).

v4.1.1...v5.0.0