Release notes#
MKE 4.2.1 is a feature release of Mirantis Kubernetes Engine 4. It adds scheduled and encrypted backups, authenticated registry pulls, and in-place infrastructure changes for existing AWS and vSphere child clusters. In addition, MKE 4.2.1 carries forward a further set of MKE 3 settings during upgrade, introduces per-child-cluster version gating, and expands mkectl with commands for control plane node management, pre-installation checks, certificate management, and account administration.
With version 4.2.1, the MKE 4 platform moves to k0rdent Enterprise 1.4.1 and Calico 3.31.7, and adds support for Ubuntu 26.04 and RHEL 9.8. The release also closes a large number of issues in the area of backup restore.
Important
Before upgrading to MKE 4.2.1, make sure to read the
Upgrade details and Known issues
sections of these release notes, as MKE 4.2.1 includes behavior changes that
affect existing clusters and automation. Most notably, the mkectl backup
command now requires either the --passphrase or the --no-passphrase
option, and MKE 3 proxy settings are not migrated during upgrade.
| Release Date | Version | Highlights |
|---|---|---|
| 15-OCT-2026 | 4.2.1 |
|