This means the site is robust, but we anticipate needing more user testing and changes before it is "production-ready" and can fully replace https://pypi.python.org . We hope to complete the transition before the end of April 2018.
We're still working to ensure the new codebase and infrastructure are reliable. So please don't rely on it (yet) unless you can handle the occasional minor outage.
But we want you to try the new PyPI, test it, and tell us if you have any problems. More at The Python Software Foundation main blog.
Thank you.
-Sumana Harihareswara on behalf of the PyPI Team
-Sumana Harihareswara on behalf of the PyPI Team