File system upgrade

After upgrading to a version with a newer ZFS filesystem, the following notification will be displayed upon first access:

Zpools available for ZFS filesystem upgrade Upgrading Zpools to the latest ZFS file system is recommended. Although the file system upgrade is absolutely safe for your data and its integrity and will only take few minutes please be aware that this operation cannot be undone and accessing this zpool data will not be possible with older software versions. In order to upgrade a single Zpool, please use “Upgrade file system" from Zpool's option menu.

Additionally, the zpool itself will display the following zpool status:

Some supported features are not enabled on the pool. The pool can still be used but it is recommended to upgrade it in order to fully utilize all system features. Action: Upgrade the pool using "Upgrade file system" in pool options menu. Once this is done, the pool will no longer be accessible by software that does not support new features.

As prompted, expand the zpool options and choose "Upgrade file system":

The following windows will appear. Type ‘upgrade’ and click the Upgrade button to proceed:

Once completed, the system will notify you that the zpool has been updated successfully.