diff --git a/config/config.msft.yaml b/config/config.msft.yaml
index 22d5ffe29..1f028ea2f 100644
--- a/config/config.msft.yaml
+++ b/config/config.msft.yaml
@@ -33,7 +33,7 @@ defaults:
       istioctlVersion: "1.24.1"
       tag: "prod-stable"
       targetVersion: "asm-1-23"
-      versions: "\"asm-1-22\", \"asm-1-23\""
+      versions: ["\"asm-1-22\", \"asm-1-23\""]
 
   # MGMT cluster specifics
   mgmt:
diff --git a/config/config.schema.json b/config/config.schema.json
index 80c303aad..ca8a4a3ec 100644
--- a/config/config.schema.json
+++ b/config/config.schema.json
@@ -675,7 +675,7 @@
               },
               "versions": {
                 "description": "The current istio version in the AKS cluster",
-                "type": "string"
+                "type": "array"
               },
               "targetVersion": {
                 "description": "The target istio version that will be updated to",
diff --git a/dev-infrastructure/configurations/svc-cluster.tmpl.bicepparam b/dev-infrastructure/configurations/svc-cluster.tmpl.bicepparam
index 20f37500b..5decc1ffc 100644
--- a/dev-infrastructure/configurations/svc-cluster.tmpl.bicepparam
+++ b/dev-infrastructure/configurations/svc-cluster.tmpl.bicepparam
@@ -1,7 +1,7 @@
 using '../templates/svc-cluster.bicep'
 
 param kubernetesVersion = '{{ .kubernetesVersion }}'
-param istioVersion = {{ .svc.istio.versions }}
+param istioVersion = [{{ .svc.istio.versions }}]
 param vnetAddressPrefix = '{{ .vnetAddressPrefix }}'
 param subnetPrefix = '{{ .subnetPrefix }}'
 param podSubnetPrefix = '{{ .podSubnetPrefix }}'