This is the first release candidate for Podman v4.0.0. This is a large release with several breaking changes to the API, focusing on a complete rewrite of the Podman network stack for better support of IPv6 and Docker compatibility. Some network stack changes (e.g. the Netavark network creation tool) are not yet ready for testing, but many aspects (including the --ipv6 flag for static IPv6 addresses) are.
Full release notes are not available with this RC, but should be available in the next one.
Expected release for Podman v4.0.0 final is in early February.