This page describes how to upgrade one Mender client version to a different Mender client version.

Minor and patch versions

If you are upgrading from one minor version to another, such as 3.4.0 -> 3.5.0, or from one patch version to another patch version, such as 3.5.1 -> 3.5.2, then no manual intervention is needed. Minor and patch versions are always backwards compatible. This follows from Semantic Versioning, which is described in more detail on the Compatibility page.

Major versions

New major versions may come with changes that require manual migration steps. Changes of this sort are sometimes necessary to fix problems that cannot be dealt with in minor releases, or enable new behaviors that conflict with existing behaviors in some way.

Upgrade the Mender client 3.x series to 4.0.0 or later


In Mender Client 4.0.0, the service was split into several smaller components. Previously the mender binary tool handled everything; now there are several smaller ones with distinct roles:

  • mender-auth for handling server communication and authentication
  • mender-setup for handling Mender configuration setup
  • mender-snapshot for handling snapshotting of live filesystems
  • mender-update for handling updates.

Following that change, the Linux systemd service was also split from mender-client into mender-authd and mender-updated.

The following features and config are not available in Mender client 4.0.0 and later:

In Mender client 4.0.0 and later the rootfs-image update type is no longer embedded in the client codebase but is treated as any other external update module. A binary CLI tool mender-flash now gets installed as part of the Mender client to serve the needs of the external rootfs update module.

Upgrade using Debian packages

In the Mender APT repositories mender-client package corresponds to the Mender Client written in Go (version 3.x.y). This package is installed by default from our Express installation script. To upgrade from the legacy Mender Client to the 4.x series on Debian and Ubuntu, you can install the mender-client4 running:

apt-get install mender-client4

This package will automatically install:

  • a mender-auth package for server authentication:
    • provides the mender-auth binary
    • installs the mender-authd systemd service
  • a mender-update package for doing updates:
    • provides the mender-update binary
    • installs the mender-updated systemd service
  • the mender-flash tool
  • the mender-setup tool
  • the mender-snapshot tool

In addition, this package will also automatically remove:

  • Legacy mender-client package:
    • removing the mender binary
    • disabling mender-client systemd service

After the upgrade, please update your scripts invoking the mender CLI interface to use the correct binaries (mender-auth or mender-update).

For old Debian and Ubuntu distributions, if the Mender add-ons Debian packages (e.g., mender-connect and mender-configure) are already installed in the system, the upgrade can fail with an error message similar to this:

The following packages have unmet dependencies:
 mender-client4 : Conflicts: mender-client but 1:3.5.2-1+debian+buster is to be installed
E: Unable to correct problems, you have held broken packages.

In this case, ensure to upgrade the Mender add-ons Debian packages at the same time, for example running:

apt-get install mender-update mender-client4

Upgrade using Yocto

Mender client version 4.0.0 or later will automatically be built on Yocto 5.0 (scarthgap) and later. If you want to enable building of Mender client version 4.0.0 or later while on Yocto 4.0 (kirkstone) or older, please refer to this specific section in our Troubleshoot guide.

Migration steps

Regardless of whether you are using Yocto or a Debian package, there are some migration steps which are required. When referring to "scripts" below, we mean any Update Module, State Script, or other script which executes on the device. All scripts that ship with Mender, and which you have not modified, do not need to be changed, since they will be auto-updated by the package manager.

  1. If any scripts call this command:

    • mender bootstrap Then they need to be changed to call mender-auth bootstrap instead of mender bootstrap.
  2. If any scripts call this command:

    • mender setup Then they need to be changed to call mender-setup instead of mender setup.
  1. If any scripts call this command:

    • mender snapshot Then they need to be changed to call mender-snapshot instead of mender snapshot. Note that if you are using snapshotting through mender-artifact's "ssh" feature, then you need at least mender-artifact version 3.11.0.
  2. If any scripts call one of these commands:

    • mender check-update
    • mender commit
    • mender install
    • mender rollback
    • mender send-inventory
    • mender show-artifact
    • mender show-provides Then they need to be changed to call mender-update <COMMAND> instead of mender <COMMAND>.
  3. If any scripts call one of these commands:

    • mender daemon Then you will need several changes. Since mender-auth and mender-update are now separate daemons, you will need to start both of them, with mender-auth daemon and mender-update daemon, respectively.
  4. If any scripts call either journalctl or systemctl with mender-client as an argument, you will need to change that. mender-client service has been replaced by two services mender-authd and mender-updated.

We welcome contributions to improve this documentation. To submit a change, use the Edit link at the top of the page or email us at .