It’s just a major version release of the Python open source package, so there aren’t “cloud” implications: 2.X will be backwards compatible with cloud, ie there’s no “shutoff date” for 2.X.
We’ll release security patches to fix CVEs should any arise in 2.X, for 6 months from when 3.0 is generally available.
After GA, most of our attention and new features will be in 3.X (though we may opportunistically back port features to 2.X).