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Since February 16, 2026: what GPT-5.6 Luna cannot know

GPT-5.6 Luna was trained on data up to February 16, 2026. Since then, 403 models, APIs and runtimes have reached their end date and packages have shipped 214,296 breaking changes. Code it writes from memory can still use any of them.

Knowledge cutoff February 16, 2026

On this page

The model ID is gpt-5.6-luna, from OpenAI, released July 9, 2026. The endings and the package changes below came after its training data ends, so they are not in what the model learned.

Ended since February 16, 2026

403 models, APIs and runtimes have reached their end date since the cutoff. The newest of each:

AI models

And 372 more on the calendar.

Still ahead

450 end dates are still ahead. Some were announced after the cutoff, so the model may write what they end. The soonest of each:

AI models

APIs

And 420 more on the calendar.

Packages that changed most

Since the cutoff, package versions shipped 214,296 breaking changes, and 42,880 security advisories were published. The packages with the most breaking changes in versions released since:

  • happy-dom npm, 2,562 breaking changes, newest in 21.0.4 (October 20, 2026)
  • skit.flurlhttpclient.wechat.api NuGet, 2,398 breaking changes, newest in 4.0.0 (November 13, 2026)
  • langfuse PyPI, 2,397 breaking changes, newest in 5.1.0 (October 30, 2026)
  • cloudflare npm, 2,014 breaking changes, newest in 7.0.0 (July 9, 2026)
  • @types/three npm, 1,884 breaking changes, newest in 0.187.0 (October 30, 2026)
  • three npm, 1,884 breaking changes, newest in 0.187.0 (October 30, 2026)
  • @huggingface/transformers npm, 1,727 breaking changes, newest in 4.3.0 (September 16, 2026)
  • azure-search-documents PyPI, 1,692 breaking changes, newest in 12.0.0 (May 1, 2026)
  • qcodes PyPI, 1,602 breaking changes, newest in 0.63.0 (November 12, 2026)
  • typescript npm, 1,586 breaking changes, newest in 7.0.2 (July 8, 2026)

Check before it writes

Run npx since-dev init in a repository and your coding agent checks a version or a model ID before it writes one, whatever model it runs on. To see what a repository already uses that has ended, scan it, or run npx since-dev inside it.

Knowledge cutoffs are from models.dev (MIT License). A cutoff given as a month is read as that month’s last day.

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Put your code on continuous maintenance.

Scan a public repository now, or give your agent one line.

See how out of date your code is.

Any public GitHub repository. No sign-in.

Tell your agent what changed since it was trained.

claude mcp add --transport http since https://api.since.dev/mcp
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