Changed Block Tracking (CBT) for Kubernetes storage CSI drivers initially launched as Alpha in September 2025. This feature enhances storage operations by tracking changes within block volumes. The Alpha announcement details its motivation, core components, and usage. CBT currently only supports block volumes, excluding file-based storage. The recent v1.0.0 release of the external-snapshot-metadata project has promoted this functionality to Beta.The primary update in the Beta phase is the upgrade of the SnapshotMetadataService Custom Resource Definition (CRD) from v1alpha1 to v1beta1. While the schema remains the same, the old v1alpha1 version has been removed, requiring users to adapt. To transition from Alpha to Beta, users must re-apply the CRD definition, update their manifests to use the new API version, and adjust any client or controller code. This migration is a manual, one-time process.The Beta version necessitates a minimum Kubernetes version of 1.33 and CSI spec version 1.10 or newer. The compatible container image is csi-snapshot-metadata:v1.0.0. To test the feature, ensure your CSI driver supports snapshots and includes the external-snapshot-metadata sidecar. Install the v1beta1 CRD and create a SnapshotMetadataService resource for your driver. Then, use a lister tool or custom implementation to interact with the GetMetadataAllocated and GetMetadataDelta functions.The development team is now focusing on broader CSI driver adoption and gathering operational feedback during the Beta period. They encourage CSI driver maintainers to evaluate adding support and backup application developers to provide input on streaming clients and the iterator package. Further information can be found in the CSI developer documentation, KEP-3314, the external-snapshot-metadata repository, the gRPC schema, and the snapshot-metadata-lister example. Contributions to this feature have been significant, and interested individuals are encouraged to engage with SIG Storage and the Data Protection Working Group.