In this section, you’ll learn how to manually upgrade the Longhorn Engine from the Longhorn UI.

Always make backups before upgrading the Longhorn engine images.

Follow these steps if the live upgrade is not available, or if the volume is stuck in degraded state:

1. Select all the volumes using batch selection. Click the batch operation button Upgrade Engine, and choose the engine image available in the list. It’s the default engine shipped with the manager for this release.
2. Resume all workloads. Any volume not part of a Kubernetes workload must be attached from the Longhorn UI.

Live upgrade is supported for upgrading from v1.4.x (< v1.4.1) or v1.3.x to v1.4.1.

Live upgrade should only be done with healthy volumes.

1. Select the volume you want to upgrade.
2. Select the engine image you want to upgrade to.
   1. Normally it’s the only engine image in the list, since the UI exclude the current image from the list.
3. Click OK.

During the live upgrade, the user will see double number of the replicas temporarily. After upgrade complete, the user should see the same number of the replicas as before, and the field of the volume should be updated.

After you’ve done upgrade for all the images, select from Longhorn UI. Now you should able to remove the non-default image.