Release notes can be found at https://projectcalico.docs.tigera.io/archive/v3.21/release-notes/

Attached to this release are the following artifacts:

• release-v3.21.4.tgz: container images, binaries, and kubernetes manifests.
• calico-windows-v3.21.4.zip: Calico for Windows.
• tigera-operator-v3.21.4.tgz: Calico Helm v3 chart.

Notes:

• v3.21.4 is a rebuild of v3.21.3 to fix build metadata.
• v3.21.4 does not have corresponding OpenStack deb / rpm packages.