diff --git a/toscaparser/extensions/wse/TOSCA_wse_definition_1_0_0.yaml b/toscaparser/extensions/wse/TOSCA_wse_definition_1_0_0.yaml
index 68142b70ebad1f8e30f9772c5f86673e6fcfee01..b8d71d007af0e6bdc132527561e77c0ee3748893 100644
--- a/toscaparser/extensions/wse/TOSCA_wse_definition_1_0_0.yaml
+++ b/toscaparser/extensions/wse/TOSCA_wse_definition_1_0_0.yaml
@@ -854,6 +854,18 @@ policy_types:
       start_first:
         type: boolean
         description: Rancher only
+      maxUnavailable:
+        type: string
+        description: |
+          The maximum number of pods that can be unavailable during the update. Value
+          can be an absolute number (ex: 5) or a percentage of desired pods (ex:
+          10%). Absolute number is calculated from percentage by rounding down. This
+          can not be 0 if MaxSurge is 0. Defaults to 25%. Example: when this is set
+          to 30%, the old ReplicaSet can be scaled down to 70% of desired pods
+          immediately when the rolling update starts. Once new pods are ready, old
+          ReplicaSet can be scaled down further, followed by scaling up the new
+          ReplicaSet, ensuring that the total number of pods available at all times
+          during the update is at least 70% of desired pods.
   tosca.policies.wise2c.Wildcard:
     derived_from: tosca.policies.Roo
     properties: