OpenAI's Python SDK swaps HTTPX for HTTPX2 and drops the certifi bundle

The openai-python SDK now ships HTTPX2 by default, with `DefaultHttpx2Client` and `DefaultAsyncHttpx2Client` preserving the recommended timeout, pool, and redirect settings. The breaking change is TLS trust, not the API surface — HTTPX2 verifies against the OS trust store instead of certifi, so minimal containers, corporate TLS-inspecting proxies, and custom certifi bundles fail verification until `SSL_CERT_FILE` or `SSL_CERT_DIR` is set. Test suites break too: RESPX setups patching legacy HTTPX cannot intercept the default client, and injecting a legacy `httpx.Client` requires `cast(Any, ...)` to pass type checking.

Source: github.com ↗