Change feed / 2026-06-30
Claude Sonnet 5 released; Sonnet 4.5 moves to Legacy
Anthropic released Claude Sonnet 5 (claude-sonnet-5) with a system card. Sonnet 4.5 is now listed under Legacy models with a tentative retirement floor of 2026-09-29 under the 60-day-notice policy.
Evidencequoted verbatim from the source
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Plain
ModelRiskIndex. "Claude Sonnet 5 released; Sonnet 4.5 moves to Legacy." Change feed, 2026-06-30. https://modelriskindex.com/changes/claude-sonnet-5-release
BibTeX
@misc{mri-2026-06-30,
title = {Claude Sonnet 5 released; Sonnet 4.5 moves to Legacy},
author = {{ModelRiskIndex}},
year = {2026},
note = {Change feed, 2026-06-30},
url = {https://modelriskindex.com/changes/claude-sonnet-5-release}
}Please cite the dated entry rather than the site root. Every assessment here is a point-in-time judgment bound to evidence retrieved on a specific date — an undated citation asserts something the data does not.
