29.2.1

Release date

Name

Upstream release

2026-MAR-24

MCR 29.2.1

Moby 29.2.1 and Docker CLI 29.2.1

Highlights

Enhancement

Detail

Minimum API 1.40

The minimum API is now 1.40, up from the previous minimum of 1.13. The new minimum API maps back to MCR 19.03. All clients must use this API version at the least with MCR 29.2.1.

IPv6 improvements

The last several upstream Moby versions have brought significant improvements to the product in terms of the stability of container IPv6 network support.

With MCR 29.2, ip6tables is no longer gated behind the experimental configuration option, and is now enabled for Linux bridge networks by default. This makes IPv4 and IPv6 behaviors consistent with each other.

Refer to the upstream release notes for full details on IPv6 improvements

Device code login for the official Docker registry

The MCR CLI now includes the upstream Docker CLI device code login flow for the official Docker Hub registry.

containerd image store

The containerd image store is now the default storage backend for fresh MCR installations, while upgraded systems will continue to use the legacy graph drivers until the containerd image store is manually enabled.

Refer to the Docker containerd image store documentation for exhaustive information.

IPAM allocation statistics

Networks now include a Status field that indicates IPAM allocations use for the subnets that are assigned to the network. As such, users can now tell how many open addresses remain available for allocation.

New Swarm service options

Options for memory swap settings <> and OOM score adjustment in Swarm are now available.

API and SDK improvements

Many small changes to the API and SDK, targeted to third-party developers.

Important

Due to the upgrade of containerd from 1.x to 2.x, before you upgrade from a previous MCR major release to MCR 29.2.1 you must upgrade containerd.io before you upgrade docker-ee. In the event that you have upgraded both components at the same time and some of the containers that should have restarted remain stopped, you can get them running again by restarting MCR with the systemctl restart docker command.

Changelog

MCR 29.2.1 comprises the Moby 29.2.1 upstream release. In addition, changes are included for the interceding upstream 26.0, 26.1, 27.0, 28.0, 28.1, 28.2, 28.3, 28.4, 28.5, 29.0, and 29.1 versions, for which there was no MCR releases.

Changes specific to MCR

Note

The MCR-specific changes detailed herein are backported from the upstream Moby 29.3.0 release.

  • Fixed an issue wherein dockerd --register-service and dockerd --unregister-service broke whenever such system dependencies as the Windows Containers feature were not installed.

  • Fix made to a missing error check in ContainerTop on Windows that could cause a nil pointer panic.

  • Fixed an issue that caused container DNS configuration corruption to occur during the reloading of the Engine configuration.

  • Restoration of API compatibility back to v1.40.

  • Pruning images no longer fails early due to layer size errors.

Changes from upstream

The upstream pull requests detailed in the sections that follow are those that pertain to the MCR product. For the complete list of changes and pull requests upstream, refer to the GitHub milestones.

What is new
Removed

  • Experimental Graphdriver plugins, which were not maintained following their inroduction.

  • Fluent logger option fluentd-async-connect, which was deprecated in version 20.10.

  • Configuration parameter api-cors-header and the corresponding flag on dockerd.

  • moby/moby#50832 GET /events fields” status, id, and from were deprecated in API v1.22 and removed in API v1.52 and later.

Deprecated

  • docker/cli#50832 --pause flag for docker commit command, which is deprecated in favor of --no-pause.

  • moby/moby#51111 cgroups v1

  • moby/moby#47556, docker/cli#4928 Unauthenticated TCP connections. Exposing the daemon for TCP connections without TLS authentication is not a supported configuration, as this configuration typically provides anonymous root access to your machine.

    Any attempts to configure the daemon to start with an unsecured TCP socket will result in various alerts and warnings.

Bug fixes and enhancements

  • The --time option for the docker stop and docker restart commands is renamed --timeout.

GitHub milestones

The GitHub milestones offer full detail on the pull requests and changes as they correlate to the upstream Moby 26.0, 26.1, 27.0, 28.0, 28.1, 28.2, 28.3, 28.4, 28.5, 29.0, 28.1, and 29.2 releases.

Major component versions

Version detail for the major components that comprise MCR 29.2.1 is presented in the table below:

Component

Upstream Version

Mirantis Version

Moby

29.2.1

29.2.1m1

Docker CLI

29.2.1

29.2.1m1

containerd

2.2.1

2.2.1m1

runc

1.4.0

1.4.0m1

cri-dockerd

0.3.23

–

buildx

0.32.1

0.32.1m1

Fipster (Go runtime)

go1.25.7-m1

–

buildkit

0.27.1

–

rootlesskit

2.3.6

–

Docker Compose CLI plugin

5.0.2

5.0.2m1

Platform test detail

Platform

Kernel tested

Oracle Linux 9.7

5.14.0-611.41.1.el9_7.x86_64

Oracle Linux 9.6

5.14.0-570.51.1.0.1.el9_6.x86_64

Oracle Linux 8.6

4.18.0-477.27.1.el8_8.x86_64

RHEL 10.0

6.12.0-124.45.1.el10_1.x86_64

RHEL 9.7

5.14.0-611.36.1.el9_7.x86_64

RHEL 9.6

5.14.0-570.94.1.el9_6.x86_64

RHEL 9.4

5.14.0-427.111.1.el9_4.x86_64

RHEL 8.10

4.18.0-553.100.1.el8_10.x86_64

Rocky 9.7

5.14.0-611.5.1.el9_7.x86_64

Rocky 9.6

5.14.0-570.17.1.el9_6.x86_64

Rocky 8.10

4.18.0-553.el8_10.x86_64

SLES17 SP7

6.4.0-150700.53.28-default

SLES15 SP6

6.4.0-150600.23.84-default

Ubuntu 24.04

6.17.0-1007-aws

Ubuntu 22.04

6.8.0-1050-aws

Windows 2022 Core

10.0 20348 (20348.2849.amd64fre.fe_release_svc_prod1.241101-1732)

Windows 2025 MCR Only

10.0 26100 (26100.32370.amd64fre.lt_release_svc_prod1.260205-1739)