diff --git a/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp4.22-upgrade.yaml b/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp4.22-upgrade.yaml
index a8e4a9187d0b1..52531c2abf28f 100644
--- a/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp4.22-upgrade.yaml
+++ b/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp4.22-upgrade.yaml
@@ -44,6 +44,7 @@ tests:
     dependencies:
       OPENSHIFT_INSTALL_RELEASE_IMAGE_OVERRIDE: release:initial
     env:
+      ACM_SUBSCRIPTION_NAMESPACE: ocm
       BASE_DOMAIN: cspilp.interop.ccitredhat.com
       COMPUTE_NODE_REPLICAS: "6"
       COMPUTE_NODE_TYPE: m6a.2xlarge
@@ -79,6 +80,7 @@ tests:
     - ref: interop-opp-preflight
     - ref: interop-opp-upgrade
     - ref: cucushift-upgrade-healthcheck
+    - ref: interop-opp-product-upgrade-acm
     - ref: interop-opp-smoke
 zz_generated_metadata:
   branch: main
diff --git a/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp5.0-upgrade.yaml b/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp5.0-upgrade.yaml
index 6573ee6e9e007..841a1a363a3f0 100644
--- a/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp5.0-upgrade.yaml
+++ b/ci-operator/config/stolostron/policy-collection/stolostron-policy-collection-main__ocp5.0-upgrade.yaml
@@ -44,6 +44,7 @@ tests:
     dependencies:
       OPENSHIFT_INSTALL_RELEASE_IMAGE_OVERRIDE: release:initial
     env:
+      ACM_SUBSCRIPTION_NAMESPACE: ocm
       BASE_DOMAIN: cspilp.interop.ccitredhat.com
       COMPUTE_NODE_REPLICAS: "6"
       COMPUTE_NODE_TYPE: m6a.2xlarge
@@ -77,6 +78,7 @@ tests:
     - ref: interop-opp-preflight
     - ref: interop-opp-upgrade
     - ref: cucushift-upgrade-healthcheck
+    - ref: interop-opp-product-upgrade-acm
     - ref: interop-opp-smoke
 zz_generated_metadata:
   branch: main
diff --git a/ci-operator/step-registry/interop/opp/product-upgrade/OWNERS b/ci-operator/step-registry/interop/opp/product-upgrade/OWNERS
new file mode 100644
index 0000000000000..41d144d3728a2
--- /dev/null
+++ b/ci-operator/step-registry/interop/opp/product-upgrade/OWNERS
@@ -0,0 +1,3 @@
+approvers: &owners
+- cspi-qe-ocp-lp
+reviewers: *owners
diff --git a/ci-operator/step-registry/interop/opp/product-upgrade/acm/OWNERS b/ci-operator/step-registry/interop/opp/product-upgrade/acm/OWNERS
new file mode 100644
index 0000000000000..41d144d3728a2
--- /dev/null
+++ b/ci-operator/step-registry/interop/opp/product-upgrade/acm/OWNERS
@@ -0,0 +1,3 @@
+approvers: &owners
+- cspi-qe-ocp-lp
+reviewers: *owners
diff --git a/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-commands.sh b/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-commands.sh
new file mode 100755
index 0000000000000..f1f28f1c71cef
--- /dev/null
+++ b/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-commands.sh
@@ -0,0 +1,427 @@
+#!/bin/bash
+set -euxo pipefail
+shopt -s inherit_errexit
+
+ACM_TARGET_CHANNEL="${ACM_TARGET_CHANNEL:-}"
+ACM_UPGRADE_TIMEOUT="${ACM_UPGRADE_TIMEOUT:-30m}"
+ACM_SUBSCRIPTION_NAME="${ACM_SUBSCRIPTION_NAME:-advanced-cluster-management}"
+ACM_SUBSCRIPTION_NAMESPACE="${ACM_SUBSCRIPTION_NAMESPACE:-open-cluster-management}"
+
+ARTIFACT_DIR="${ARTIFACT_DIR:-/tmp/artifacts}"
+mkdir -p "${ARTIFACT_DIR}"
+
+function CollectDiagnostics () {
+    typeset artifactFile="${ARTIFACT_DIR}/acm-upgrade-diagnostics.txt"
+    {
+        printf '=== ACM Operator Upgrade Diagnostics ===\n\n'
+        printf '=== Subscription ===\n'
+        oc get subscription "${ACM_SUBSCRIPTION_NAME}" -n "${ACM_SUBSCRIPTION_NAMESPACE}" -o yaml 2>&1 || true
+        printf '\n=== CSVs in %s ===\n' "${ACM_SUBSCRIPTION_NAMESPACE}"
+        oc get csv -n "${ACM_SUBSCRIPTION_NAMESPACE}" 2>&1 || true
+        printf '\n=== InstallPlan ===\n'
+        oc get installplan -n "${ACM_SUBSCRIPTION_NAMESPACE}" 2>&1 || true
+        printf '\n=== MCE CSVs ===\n'
+        oc get csv -n multicluster-engine 2>&1 || true
+        printf '\n=== Pods not Ready ===\n'
+        oc get pods -n "${ACM_SUBSCRIPTION_NAMESPACE}" --field-selector=status.phase!=Running,status.phase!=Succeeded 2>&1 || true
+        oc get pods -n multicluster-engine --field-selector=status.phase!=Running,status.phase!=Succeeded 2>&1 || true
+    } > "${artifactFile}"
+    true
+}
+
+trap 'if (( $? != 0 )); then CollectDiagnostics; fi' EXIT
+
+function GetCurrentCsv () {
+    oc get subscription "${ACM_SUBSCRIPTION_NAME}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.status.currentCSV}' || true
+}
+
+function GetCsvPhase () {
+    typeset csvName="$1"
+    oc get csv "${csvName}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.status.phase}' || true
+}
+
+function GetInstalledVersion () {
+    typeset csvName
+    csvName="$(GetCurrentCsv)"
+    if [[ -z "${csvName}" ]]; then
+        return 1
+    fi
+    oc get csv "${csvName}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.spec.version}' || true
+}
+
+function GetCurrentChannel () {
+    oc get subscription "${ACM_SUBSCRIPTION_NAME}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.spec.channel}' || true
+}
+
+function ResolveTargetChannel () {
+    if [[ -n "${ACM_TARGET_CHANNEL}" ]]; then
+        echo "${ACM_TARGET_CHANNEL}"
+        return 0
+    fi
+
+    typeset currentChannel
+    currentChannel="$(GetCurrentChannel)"
+    if [[ -z "${currentChannel}" ]]; then
+        echo >&2 "ERROR: Cannot determine current subscription channel"
+        return 3
+    fi
+
+    typeset catalogNamespace
+    catalogNamespace="$(oc get subscription "${ACM_SUBSCRIPTION_NAME}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.spec.sourceNamespace}' || true)"
+
+    typeset packageName
+    packageName="$(oc get subscription "${ACM_SUBSCRIPTION_NAME}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.spec.name}' || true)"
+
+    typeset channels
+    channels="$(oc get packagemanifest "${packageName}" \
+        -n "${catalogNamespace}" \
+        -o jsonpath='{.status.channels[*].name}' || true)"
+
+    if [[ -z "${channels}" ]]; then
+        echo >&2 "ERROR: No channels found in packagemanifest for ${packageName}"
+        return 3
+    fi
+
+    typeset currentVersion nextChannel=""
+    currentVersion="$(echo "${currentChannel}" | grep -oE '[0-9]+\.[0-9]+' || true)"
+
+    typeset -a channelList
+    read -ra channelList <<< "${channels}"
+    for ch in "${channelList[@]}"; do
+        typeset chVersion
+        chVersion="$(echo "${ch}" | grep -oE '[0-9]+\.[0-9]+' || true)"
+        if [[ -z "${chVersion}" ]]; then
+            continue
+        fi
+        if [[ -z "${currentVersion}" ]]; then
+            nextChannel="${ch}"
+            break
+        fi
+        typeset currentMajor currentMinor chMajor chMinor
+        currentMajor="${currentVersion%%.*}"
+        currentMinor="${currentVersion##*.}"
+        chMajor="${chVersion%%.*}"
+        chMinor="${chVersion##*.}"
+
+        if (( chMajor > currentMajor )) || \
+           (( chMajor == currentMajor && chMinor > currentMinor )); then
+            if [[ -z "${nextChannel}" ]]; then
+                nextChannel="${ch}"
+            else
+                typeset nextVersion nextMajor nextMinor
+                nextVersion="$(echo "${nextChannel}" | grep -oE '[0-9]+\.[0-9]+' || true)"
+                nextMajor="${nextVersion%%.*}"
+                nextMinor="${nextVersion##*.}"
+                if (( chMajor < nextMajor )) || \
+                   (( chMajor == nextMajor && chMinor < nextMinor )); then
+                    nextChannel="${ch}"
+                fi
+            fi
+        fi
+    done
+
+    if [[ -z "${nextChannel}" ]]; then
+        echo >&2 "ERROR: No upgrade channel found newer than ${currentChannel}"
+        return 3
+    fi
+
+    echo "${nextChannel}"
+    true
+}
+
+function WaitForCsvSucceeded () {
+    typeset previousCsv="$1"
+    typeset timeoutSeconds
+    timeoutSeconds="$(ParseTimeout "${ACM_UPGRADE_TIMEOUT}")"
+    typeset startTime elapsed newCsv phase
+    startTime="$(date +%s)"
+
+    while true; do
+        elapsed="$(( $(date +%s) - startTime ))"
+        if (( elapsed > timeoutSeconds )); then
+            echo >&2 "ERROR: Timeout (${ACM_UPGRADE_TIMEOUT}) waiting for CSV upgrade"
+            return 2
+        fi
+
+        newCsv="$(GetCurrentCsv)"
+        if [[ -z "${newCsv}" || "${newCsv}" == "${previousCsv}" ]]; then
+            sleep 10
+            continue
+        fi
+
+        phase="$(GetCsvPhase "${newCsv}")"
+        echo "  CSV: ${newCsv}  Phase: ${phase}  (${elapsed}s elapsed)"
+
+        case "${phase}" in
+            Succeeded)
+                return 0
+                ;;
+            Failed)
+                echo >&2 "ERROR: CSV ${newCsv} entered Failed phase"
+                return 1
+                ;;
+            *)
+                sleep 15
+                ;;
+        esac
+    done
+}
+
+function ParseTimeout () {
+    typeset input="$1"
+    typeset minutes=0 seconds=0
+    if [[ "${input}" =~ ^([0-9]+)m$ ]]; then
+        minutes="${BASH_REMATCH[1]}"
+    elif [[ "${input}" =~ ^([0-9]+)s$ ]]; then
+        seconds="${BASH_REMATCH[1]}"
+    elif [[ "${input}" =~ ^([0-9]+)h$ ]]; then
+        minutes="$(( BASH_REMATCH[1] * 60 ))"
+    elif [[ "${input}" =~ ^([0-9]+)$ ]]; then
+        minutes="${input}"
+    else
+        echo >&2 "WARNING: Unrecognized timeout format '${input}'; defaulting to 30m"
+        minutes=30
+    fi
+    echo "$(( minutes * 60 + seconds ))"
+    true
+}
+
+function ValidateMceUpgrade () {
+    echo "Validating MCE (MultiCluster Engine) upgrade..."
+    typeset mceCsv
+    mceCsv="$(oc get csv -n multicluster-engine \
+        -o jsonpath='{.items[?(@.spec.displayName=="multicluster engine for Kubernetes")].metadata.name}' \
+        || true)"
+
+    if [[ -z "${mceCsv}" ]]; then
+        mceCsv="$(oc get csv -n multicluster-engine \
+            -l operators.coreos.com/multicluster-engine.multicluster-engine= \
+            -o jsonpath='{.items[0].metadata.name}' || true)"
+    fi
+
+    if [[ -z "${mceCsv}" ]]; then
+        echo "WARNING: MCE CSV not found; skipping MCE validation"
+        return 0
+    fi
+
+    typeset mcePhase
+    mcePhase="$(oc get csv "${mceCsv}" -n multicluster-engine \
+        -o jsonpath='{.status.phase}' || true)"
+
+    echo "  MCE CSV: ${mceCsv}  Phase: ${mcePhase}"
+    if [[ "${mcePhase}" != "Succeeded" ]]; then
+        echo "WARNING: MCE CSV phase is ${mcePhase}, not Succeeded"
+        typeset timeoutEnd
+        timeoutEnd="$(( $(date +%s) + 300 ))"
+        while (( $(date +%s) < timeoutEnd )); do
+            mcePhase="$(oc get csv "${mceCsv}" -n multicluster-engine \
+                -o jsonpath='{.status.phase}' || true)"
+            if [[ "${mcePhase}" == "Succeeded" ]]; then
+                echo "  MCE CSV reached Succeeded phase"
+                return 0
+            fi
+            sleep 15
+        done
+        echo >&2 "ERROR: MCE CSV did not reach Succeeded within 5 minutes"
+        return 1
+    fi
+    return 0
+}
+
+function ValidateHubHealth () {
+    echo "Validating ACM hub health post-upgrade..."
+
+    typeset mchStatus
+    mchStatus="$(oc get multiclusterhub -A \
+        -o jsonpath='{.items[0].status.phase}' || true)"
+    echo "  MultiClusterHub phase: ${mchStatus}"
+
+    if [[ "${mchStatus}" != "Running" ]]; then
+        echo "  Waiting for MCH to reach Running phase (timeout: 5m)..."
+        typeset timeoutEnd
+        timeoutEnd="$(( $(date +%s) + 300 ))"
+        while (( $(date +%s) < timeoutEnd )); do
+            mchStatus="$(oc get multiclusterhub -A \
+                -o jsonpath='{.items[0].status.phase}' || true)"
+            if [[ "${mchStatus}" == "Running" ]]; then
+                break
+            fi
+            sleep 15
+        done
+        if [[ "${mchStatus}" != "Running" ]]; then
+            echo >&2 "ERROR: MultiClusterHub did not reach Running phase"
+            return 1
+        fi
+    fi
+
+    echo "  Checking policy propagator..."
+    typeset propagatorReady=""
+    typeset -i propTimeout=300
+    typeset -i propStart
+    propStart="$(date +%s)"
+    while (( $(date +%s) - propStart < propTimeout )); do
+        propagatorReady="$(oc get pods -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+            -l name=governance-policy-propagator \
+            -o jsonpath='{.items[0].status.conditions[?(@.type=="Ready")].status}' \
+            || true)"
+        if [[ "${propagatorReady}" == "True" ]]; then
+            break
+        fi
+        sleep 15
+    done
+    echo "  Policy propagator ready: ${propagatorReady}"
+    if [[ "${propagatorReady}" != "True" ]]; then
+        echo >&2 "ERROR: Policy propagator not ready after ${propTimeout}s"
+        return 1
+    fi
+
+    echo "  Checking managed clusters..."
+    typeset clusterOutput=""
+    clusterOutput="$(oc get managedclusters --no-headers || true)"
+    typeset -i clusterCount=0
+    clusterCount="$(echo "${clusterOutput}" | grep -c . || true)"
+    typeset availableOutput=""
+    availableOutput="$(oc get managedclusters \
+        -o jsonpath='{.items[?(@.status.conditions[?(@.type=="ManagedClusterConditionAvailable")].status=="True")].metadata.name}' \
+        || true)"
+    typeset -i availableCount=0
+    availableCount="$(echo "${availableOutput}" | wc -w)"
+    echo "  Managed clusters: ${availableCount}/${clusterCount} available"
+
+    if (( clusterCount > 0 && availableCount == 0 )); then
+        echo >&2 "WARNING: All ${clusterCount} managed cluster(s) are unavailable after upgrade"
+    elif (( clusterCount > 0 && availableCount < clusterCount )); then
+        echo >&2 "WARNING: ${availableCount}/${clusterCount} managed cluster(s) available (some may be reconciling post-upgrade)"
+    fi
+
+    echo "ACM hub health validation complete"
+    return 0
+}
+
+# === Main ===
+
+function Main () {
+    typeset currentCsv currentVersion currentChannel targetChannel
+    typeset prePatchPlan planPhase installPlan localApproval
+    typeset newCsv newVersion
+
+    echo "=== ACM Operator Upgrade Step ==="
+    echo "Namespace: ${ACM_SUBSCRIPTION_NAMESPACE}"
+    echo "Subscription: ${ACM_SUBSCRIPTION_NAME}"
+    echo "Timeout: ${ACM_UPGRADE_TIMEOUT}"
+
+    currentCsv="$(GetCurrentCsv)"
+    if [[ -z "${currentCsv}" ]]; then
+        echo >&2 "ERROR: No ACM subscription found or no currentCSV set"
+        exit 3
+    fi
+
+    currentVersion="$(GetInstalledVersion)"
+    currentChannel="$(GetCurrentChannel)"
+    echo "Current: CSV=${currentCsv} Version=${currentVersion} Channel=${currentChannel}"
+
+    targetChannel="$(ResolveTargetChannel)"
+    echo "Target channel: ${targetChannel}"
+
+    prePatchPlan=""
+    if ! prePatchPlan="$(oc get subscription "${ACM_SUBSCRIPTION_NAME}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.status.installPlanRef.name}' 2>/dev/null)"; then
+        echo "WARNING: Could not query current installPlanRef; treating as empty"
+        prePatchPlan=""
+    fi
+    echo "Pre-patch InstallPlan: ${prePatchPlan:-none}"
+
+    if [[ "${targetChannel}" == "${currentChannel}" ]]; then
+        echo "Already on target channel ${targetChannel}; checking if upgrade is available..."
+        if [[ -z "${prePatchPlan}" ]]; then
+            echo "No pending upgrade on current channel; nothing to do"
+            exit 0
+        fi
+        planPhase="$(oc get installplan "${prePatchPlan}" \
+            -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+            -o jsonpath='{.status.phase}' || true)"
+        if [[ "${planPhase}" == "Complete" ]]; then
+            echo "InstallPlan ${prePatchPlan} already complete; no pending upgrade"
+            exit 0
+        fi
+        installPlan="${prePatchPlan}"
+    else
+        echo "Patching subscription channel: ${currentChannel} -> ${targetChannel}"
+        oc patch subscription "${ACM_SUBSCRIPTION_NAME}" \
+            -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+            --type merge \
+            -p "{\"spec\":{\"channel\":\"${targetChannel}\"}}"
+
+        echo "Waiting for new InstallPlan (pre-patch ref: ${prePatchPlan:-none})..."
+        sleep 10
+
+        installPlan=""
+        for _ in {1..18}; do
+            installPlan="$(oc get subscription "${ACM_SUBSCRIPTION_NAME}" \
+                -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+                -o jsonpath='{.status.installPlanRef.name}' || true)"
+            if [[ -n "${installPlan}" && "${installPlan}" != "${prePatchPlan}" ]]; then
+                break
+            fi
+            installPlan=""
+            sleep 10
+        done
+
+        if [[ -z "${installPlan}" ]]; then
+            echo >&2 "ERROR: No new InstallPlan appeared after channel change (waited 3m)"
+            exit 2
+        fi
+    fi
+
+    echo "InstallPlan: ${installPlan}"
+    localApproval="$(oc get installplan "${installPlan}" \
+        -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+        -o jsonpath='{.spec.approval}' || true)"
+    if [[ "${localApproval}" == "Manual" ]]; then
+        echo "Approving manual InstallPlan..."
+        oc patch installplan "${installPlan}" \
+            -n "${ACM_SUBSCRIPTION_NAMESPACE}" \
+            --type merge \
+            -p '{"spec":{"approved":true}}'
+    fi
+
+    echo "Waiting for ACM CSV to reach Succeeded phase..."
+    WaitForCsvSucceeded "${currentCsv}"
+    newCsv="$(GetCurrentCsv)"
+    newVersion="$(GetInstalledVersion)"
+    echo "Upgrade complete: ${currentVersion} -> ${newVersion} (CSV: ${newCsv})"
+
+    ValidateMceUpgrade
+    ValidateHubHealth
+
+    {
+        printf '=== ACM Operator Upgrade Summary ===\n'
+        printf 'Previous: %s (%s)\n' "${currentVersion}" "${currentChannel}"
+        printf 'Current:  %s (%s)\n' "${newVersion}" "${targetChannel}"
+        printf 'CSV:      %s\n' "${newCsv}"
+        printf 'Status:   SUCCESS\n'
+    } > "${ARTIFACT_DIR}/acm-upgrade-summary.txt"
+
+    if [[ -n "${SHARED_DIR:-}" ]]; then
+        echo "${newVersion}" > "${SHARED_DIR}/acm-upgraded-version"
+        echo "${targetChannel}" > "${SHARED_DIR}/acm-upgraded-channel"
+    fi
+
+    echo "=== ACM Operator Upgrade: SUCCESS ==="
+    true
+}
+
+Main "$@"
diff --git a/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.metadata.json b/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.metadata.json
new file mode 100644
index 0000000000000..2581637b16588
--- /dev/null
+++ b/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.metadata.json
@@ -0,0 +1,11 @@
+{
+	"path": "interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.yaml",
+	"owners": {
+		"approvers": [
+			"cspi-qe-ocp-lp"
+		],
+		"reviewers": [
+			"cspi-qe-ocp-lp"
+		]
+	}
+}
\ No newline at end of file
diff --git a/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.yaml b/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.yaml
new file mode 100644
index 0000000000000..53bc8d83a2808
--- /dev/null
+++ b/ci-operator/step-registry/interop/opp/product-upgrade/acm/interop-opp-product-upgrade-acm-ref.yaml
@@ -0,0 +1,49 @@
+ref:
+  as: interop-opp-product-upgrade-acm
+  from: cli
+  grace_period: 5m
+  commands: interop-opp-product-upgrade-acm-commands.sh
+  timeout: 45m
+  resources:
+    requests:
+      cpu: 100m
+      memory: 100Mi
+  env:
+    - name: ACM_TARGET_CHANNEL
+      default: ""
+      documentation: |-
+        Target subscription channel for ACM operator upgrade (e.g. release-2.13).
+        When empty, the step determines the next available channel automatically
+        by querying the catalog for channels newer than the currently installed version.
+    - name: ACM_UPGRADE_TIMEOUT
+      default: "30m"
+      documentation: |-
+        Maximum time to wait for the ACM operator upgrade to complete.
+        Covers CSV transition from Replacing to Succeeded phase.
+    - name: ACM_SUBSCRIPTION_NAME
+      default: "advanced-cluster-management"
+      documentation: |-
+        Name of the ACM Subscription resource in the target namespace.
+    - name: ACM_SUBSCRIPTION_NAMESPACE
+      default: "open-cluster-management"
+      documentation: |-
+        Namespace containing the ACM Subscription and CSV resources.
+  documentation: |-
+    Upgrades the ACM (Advanced Cluster Management) operator via OLM subscription
+    channel change and validates the upgrade completes successfully.
+
+    The step performs:
+    1. Identifies the currently installed ACM version via CSV
+    2. Patches the Subscription to the target channel (or next available)
+    3. Waits for the new CSV to reach Succeeded phase
+    4. Validates MCE (MultiCluster Engine) co-upgrade completion
+    5. Confirms hub connectivity and policy engine health
+
+    This step gates downstream product upgrades (ACS, ODF, Quay) in the
+    OPP coordinated product upgrade workflow.
+
+    Exit codes:
+      0 - upgrade successful, all health checks passed
+      1 - upgrade failed (CSV did not reach Succeeded)
+      2 - timeout waiting for upgrade
+      3 - precondition failure (no subscription found, no upgrade path)