Python 3.15 hit beta 1 feature freeze on May 7, locking in a final feature set that includes a new built-in `sentinel` (PEP 661), `frozendict`, explicit lazy imports, unpacking in comprehensions, UTF-8 as default encoding, a stable free-threaded ABI, and a new sampling profiler. The JIT compiler also improved 8–9% on x86-64. PEP 829 was accepted, deprecating code-execution via `.pth` files in favor of explicit `.start` startup files. Pydantic forked `httpx` as `httpx2` after the original stalled, with community coordination rather than conflict. Meta's Rust-based type checker Pyrefly reached 1.0, already used by Instagram, PyTorch, and NumPy. AI bug-hunting efforts using Claude Code agents found 575+ bugs in Python C extensions and 271 in Firefox. Anthropic's Code with Claude event highlighted multi-agent orchestration and the Advisor pattern for cost-efficient AI workflows. Other releases include Django 6.1 alpha, pip 26.1, PyPy 7.3.22, Pydantic AI v2 beta, and PyTorch 2.12.
