# Release Notes for v0.21.0

Release Date: May 29th, 2026

This release is based on [3.31.0](https://github.com/kata-containers/kata-containers/releases/tag/3.31.0) of Kata Containers

This release uses v0.20.0 of Trustee and guest components.
Trustee and the guest components use KBS protocol v0.4.0.

This release patches [GHSA-84rc-2q4r-45pc](https://github.com/confidential-containers/guest-components/security/advisories/GHSA-84rc-2q4r-45pc), a moderate severity advisory.

Trustee and guest components use Rust v1.90.0.

Please see the [quickstart guide](https://confidentialcontainers.org/docs/getting-started/) or [project documentation](https://confidentialcontainers.org/docs) for more information.

## Deprecation Notices
* The CAA docker provider has been deprecated since 0.20 and is planned to be removed in 0.22.
* The Fedora-based mkosi-built CAA podvm image has been deprecated since 0.20 and is planned to be removed in 0.22
* The packer-built CAA podvm image has been deprecated since 0.17 and is planned to be removed in 0.22
* The CAA csi-wrapper component is deprecated and is planned to be removed in 0.22

## What's New

* KBS supports deleting resources (with some storage backends).
* Improved TLS support in Trustee
* Improved TDX support in Trustee
* Improved SE support in Trustee
* Azure attestation policies fixed.
* TPM verifier reports AK as TCB claim.
* Trustee with ITA can attest guests with multiple devices.
* Trustee supports external plugins via gRPC.
* Basic CoRIM support in RVPS
* Trustee uses centralized storage backend.
* Attestation Agent more accurately reports what TEEs are supported on startup.

## Hardware Support

Attestation is supported and tested on three platforms: Intel TDX, AMD SEV-SNP, and IBM SEL.
Not all features have been tested on every platform, but those based on attestation
are expected to work on the platforms above.

Make sure your host platform is compatible with the hypervisor and guest kernel
provisioned by CoCo.

This release has been tested on the following stacks:

### AMD SEV-SNP

* Processor: AMD EPYC 7713
* Kernel: 6.16.0
* OS: Ubuntu 24.04 LTS
* k8s: v1.34.2 (Kubeadm)
* Kustomize: v5.7.1
* Containerd: v1.7.29

### Intel TDX

* Kernel: 6.17.0-14-generic
* OS: Ubuntu 24.04.4 LTS
* k8s: v1.35.2 (Kubeadm)
* Kustomize: v5.7.1

### IBM Secure Execution for Linux (SEL)

* Hardware: IBM Z16 LPAR
* Kernel: 6.8.0-111-generic
* OS: Ubuntu 24.04.2 LTS
* k8s: v1.35.1 (Kubeadm)
* Kustomize: v5.8.1

### NVIDIA

There are two NVIDIA runners.

* Hardware: AMD EPYC 9274F and NVIDIA Corporation GH100
* Kernel: 7.0.0-15-generic
* OS: Ubuntu 26.04
* k8s: v1.34.1
* Kustomize: v5.7.1
* Containerd: v2.3.0

## Limitations

The following are limitations and known issues with this release.

* Credentials for authenticated registries are exposed to the host.
* LUKS-based secure storage provides integrity protection, but not replay protection.
* Not all features are tested on all platforms.
* Guest pull with nydus snapshotter sometimes fails.
* Guest pull may have negative performance implications.
* `crio` support is still evolving.
* Containerd versions older than v2.3.x may have issues with guest pull.
* SELinux is not supported on the host and must be set to permissive if in use.
* A secure Kata agent policy must be used to protect the guest, but this may not support some Kubernetes commands, such as exec.
