# Claude Platform Claude Platform release notes — July 15, 2026

- Product: Claude Platform (https://whatsnew.fyi/product/claude-platform)
- Vendor: Anthropic
- Date: 2026-07-15
- Original notes: https://platform.claude.com/docs/en/release-notes/overview#july-15-2026
- Permalink: https://whatsnew.fyi/product/claude-platform/releases/2026-07-15-claude-platform-release-notes-july-15-2026

What's New is an index, not a publisher: every entry below links to the vendor's own release notes, which are the authoritative source. Entries are labelled where they are hand-curated sample data, pre-releases, or drawn from a secondary source such as a developer blog.

Reuse: the summaries, labels and curation here are © What's New. Quote freely with attribution and a link back; wholesale republication of the corpus is not permitted — terms: https://whatsnew.fyi/terms. The vendors' own release notes remain their publishers'.

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Mid-conversation system messages are available on Claude Fable 5, Claude Mythos 5, and Claude Opus 4.8, on the Claude API, Claude in Amazon Bedrock , and Google Cloud . No beta header is required. Thi…

- **added** — Mid-conversation system messages are now available on Claude Fable 5, Claude Mythos 5, and Claude Opus 4.8 via the Claude API, Claude in Amazon Bedrock, and Google Cloud