🎉 Release alert 🎉 Metaflow 2.4.0 is out now on PyPI and (soon) Conda! The release includes a breaking change for the

created_at

and

finished_at

fields in the client, several bug fixes as well as a significant rewrite of the datastore implementation (not user visible but may interest the developer community here).

just some context about the breaking change since it is so unusual for Metaflow: Metaflow provides a strong guarantee of backwards compatibility of its public-facing APIs. In other words, it should be always safe to upgrade Metaflow without having to fear of your flows or notebooks breaking. This release is exceptional since it marks the final convergence of the Metaflow version that Netflix used internally and the open-source codebase. Now everyone uses the same open-source core Metaflow. ✨ The

.created_at

and

finished_at

properties in the Client API were always meant to return a

datetime

object (as they did originally) but unintentionally they have been returning a string this in the open-source version, which got "fixed" in this release. Given that this release marks a special milestone - and the impact radius of the breaking change is hopefully small and easy to work around (see details in the release notes) - we did make the unusual choice of altering the behavior of a public API. We don't anticipate any other breaking changes in the near future, except eventual deprecation of Python 2. We apologize any inconvenience this change may cause 🙏 Note that upgrading Metaflow won't affect production flows deployed to Step Functions automatically, so in any case the change won't take effect unless you take explicit action to upgrade Metaflow and re-run

step-functions create

. We are happy to help if you need any assistance in managing the upgrade.