# Work around incorrect lintian version
        #  https://github.com/elastic/elasticsearch/issues/48573
        if [ $VERSION_ID == 10 ] ; then
            sudo apt-get install -y --allow-downgrades lintian=2.15.0
        fi
    fi
else
    cat /etc/issue || true
fi

sudo bash -c 'cat > /etc/sudoers.d/elasticsearch_vars'  << SUDOERS_VARS
    Defaults   env_keep += "ES_JAVA_HOME"

        # Work around incorrect lintian version
        #  https://github.com/elastic/elasticsearch/issues/48573
        if [ $VERSION_ID == 10 ] ; then
            sudo apt-get install -y --allow-downgrades lintian=2.15.0
        fi
    fi
else
    cat /etc/issue || true
fi

sudo bash -c 'cat > /etc/sudoers.d/elasticsearch_vars'  << SUDOERS_VARS
    Defaults   env_keep += "ES_JAVA_HOME"

	// Current version being written.
	xlVersionCurrent [4]byte
)

const (
	// Breaking changes.
	// Newer versions cannot be read by older software.
	// This will prevent downgrades to incompatible versions.
	xlVersionMajor = 1

	// Non breaking changes.
	// Bumping this is informational, but should be done
	// if any change is made to the data stored, bumping this

                    }
                    context.success("Model upgrade completed");
                    modifiedPoms.add(pomPath);
                } else {
                    // Treat invalid upgrades (including downgrades) as errors, not warnings
                    context.failure("Cannot upgrade from " + currentVersion + " to " + targetModelVersion);
                    errorPoms.add(pomPath);
                }

        "ReadWriteC -> ReadWriteA",
        "ReadWriteB -> ReadWriteC",
        "ReadWriteA -> ReadWriteB");
  }

  public void testWriteToReadLockDowngrading() {
    writeLockA.lock(); // writeLockA downgrades to readLockA
    readLockA.lock();
    writeLockA.unlock();

    lockB.lock(); // readLockA -> lockB
    readLockA.unlock();

    // lockB -> writeLockA should fail

        "ReadWriteC -> ReadWriteA",
        "ReadWriteB -> ReadWriteC",
        "ReadWriteA -> ReadWriteB");
  }

  public void testWriteToReadLockDowngrading() {
    writeLockA.lock(); // writeLockA downgrades to readLockA
    readLockA.lock();
    writeLockA.unlock();

    lockB.lock(); // readLockA -> lockB
    readLockA.unlock();

    // lockB -> writeLockA should fail

//go:generate stringer -type VersionType,ErasureAlgo -output=xl-storage-format-v2_string.go $GOFILE

const (
	// Breaking changes.
	// Newer versions cannot be read by older software.
	// This will prevent downgrades to incompatible versions.
	xlVersionMajor = 1

	// Non breaking changes.
	// Bumping this is informational, but should be done
	// if any change is made to the data stored, bumping this

### Other notable changes

* kube-up (with gce/gci and gce/coreos providers) now ensures the authentication token file contains correct tokens for the control plane components, even if the file already exists (ensures upgrades and downgrades work successfully) ([#43676](https://github.com/kubernetes/kubernetes/pull/43676), [@liggitt](https://github.com/liggitt))

* Fix GCE etcd scripts to pass in all required parameters for the etcd migration utility to correctly perform HA upgrades and downgrades ([#61956](https://github.com/kubernetes/kubernetes/pull/61956), [@jpbetz](https://github.com/jpbetz))

## Before Upgrading

* If you need to downgrade from 1.10 to 1.9.x, downgrade to v1.9.6 to ensure PV and PVC objects can be deleted properly.