OpenZFS indicates support for various ZFS features by setting feature flags on your storage pool. As you upgrade TrueNAS, and thus OpenZFS, additional feature flags may become available. Enabling or activating these new feature flags may make it impossible for your storage pool to be mounted on an earlier version, should you need to roll back TrueNAS or move your pool to another system. Therefore, it’s often recommended to not upgrade your pool with the new flags unless you know you need those features or won’t ever be rolling back.
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