diff --git a/output/openapi/elasticsearch-openapi.json b/output/openapi/elasticsearch-openapi.json
index 5827506acc..252c7e8702 100644
--- a/output/openapi/elasticsearch-openapi.json
+++ b/output/openapi/elasticsearch-openapi.json
@@ -10204,7 +10204,11 @@
                   "next_step": {
                     "$ref": "#/components/schemas/ilm.move_to_step:StepKey"
                   }
-                }
+                },
+                "required": [
+                  "current_step",
+                  "next_step"
+                ]
               }
             }
           }
@@ -67166,8 +67170,6 @@
           }
         },
         "required": [
-          "action",
-          "name",
           "phase"
         ]
       },
@@ -67376,10 +67378,7 @@
           "_shards": {
             "$ref": "#/components/schemas/_types:ShardStatistics"
           }
-        },
-        "required": [
-          "_shards"
-        ]
+        }
       },
       "indices.close:CloseIndexResult": {
         "type": "object",
@@ -67926,6 +67925,9 @@
         "properties": {
           "hidden": {
             "type": "boolean"
+          },
+          "allow_custom_routing": {
+            "type": "boolean"
           }
         }
       },
diff --git a/output/openapi/elasticsearch-serverless-openapi.json b/output/openapi/elasticsearch-serverless-openapi.json
index d2b2e81c6f..a107a9e5f1 100644
--- a/output/openapi/elasticsearch-serverless-openapi.json
+++ b/output/openapi/elasticsearch-serverless-openapi.json
@@ -45092,6 +45092,9 @@
         "properties": {
           "hidden": {
             "type": "boolean"
+          },
+          "allow_custom_routing": {
+            "type": "boolean"
           }
         }
       },
@@ -45101,10 +45104,7 @@
           "_shards": {
             "$ref": "#/components/schemas/_types:ShardStatistics"
           }
-        },
-        "required": [
-          "_shards"
-        ]
+        }
       },
       "indices.resolve_index:ResolveIndexItem": {
         "type": "object",
diff --git a/output/schema/schema-serverless.json b/output/schema/schema-serverless.json
index db51bcc59b..c597cac7aa 100644
--- a/output/schema/schema-serverless.json
+++ b/output/schema/schema-serverless.json
@@ -117251,9 +117251,20 @@
               "namespace": "_builtins"
             }
           }
+        },
+        {
+          "name": "allow_custom_routing",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "boolean",
+              "namespace": "_builtins"
+            }
+          }
         }
       ],
-      "specLocation": "indices/_types/DataStream.ts#L144-L146"
+      "specLocation": "indices/_types/DataStream.ts#L144-L147"
     },
     {
       "kind": "interface",
@@ -117264,7 +117275,7 @@
       "properties": [
         {
           "name": "_shards",
-          "required": true,
+          "required": false,
           "type": {
             "kind": "instance_of",
             "type": {
@@ -117274,7 +117285,7 @@
           }
         }
       ],
-      "specLocation": "_types/Base.ts#L91-L93"
+      "specLocation": "_types/Base.ts#L91-L94"
     },
     {
       "kind": "interface",
diff --git a/output/schema/schema.json b/output/schema/schema.json
index 4cd3a97071..e07fdc27e7 100644
--- a/output/schema/schema.json
+++ b/output/schema/schema.json
@@ -50351,7 +50351,7 @@
       "properties": [
         {
           "name": "_shards",
-          "required": true,
+          "required": false,
           "type": {
             "kind": "instance_of",
             "type": {
@@ -50361,7 +50361,7 @@
           }
         }
       ],
-      "specLocation": "_types/Base.ts#L91-L93"
+      "specLocation": "_types/Base.ts#L91-L94"
     },
     {
       "kind": "interface",
@@ -120036,7 +120036,7 @@
         "properties": [
           {
             "name": "current_step",
-            "required": false,
+            "required": true,
             "type": {
               "kind": "instance_of",
               "type": {
@@ -120047,7 +120047,7 @@
           },
           {
             "name": "next_step",
-            "required": false,
+            "required": true,
             "type": {
               "kind": "instance_of",
               "type": {
@@ -120114,7 +120114,7 @@
       "properties": [
         {
           "name": "action",
-          "required": true,
+          "required": false,
           "type": {
             "kind": "instance_of",
             "type": {
@@ -120125,7 +120125,7 @@
         },
         {
           "name": "name",
-          "required": true,
+          "required": false,
           "type": {
             "kind": "instance_of",
             "type": {
@@ -120146,7 +120146,7 @@
           }
         }
       ],
-      "specLocation": "ilm/move_to_step/types.ts#L20-L24"
+      "specLocation": "ilm/move_to_step/types.ts#L20-L25"
     },
     {
       "attachedBehaviors": [
@@ -121242,9 +121242,20 @@
               "namespace": "_builtins"
             }
           }
+        },
+        {
+          "name": "allow_custom_routing",
+          "required": false,
+          "type": {
+            "kind": "instance_of",
+            "type": {
+              "name": "boolean",
+              "namespace": "_builtins"
+            }
+          }
         }
       ],
-      "specLocation": "indices/_types/DataStream.ts#L144-L146"
+      "specLocation": "indices/_types/DataStream.ts#L144-L147"
     },
     {
       "kind": "interface",
diff --git a/output/typescript/types.ts b/output/typescript/types.ts
index 6d3264a956..31dfa54ccb 100644
--- a/output/typescript/types.ts
+++ b/output/typescript/types.ts
@@ -2809,7 +2809,7 @@ export interface ShardStatistics {
 }
 
 export interface ShardsOperationResponseBase {
-  _shards: ShardStatistics
+  _shards?: ShardStatistics
 }
 
 export interface SlicedScroll {
@@ -10447,16 +10447,16 @@ export interface IlmMigrateToDataTiersResponse {
 export interface IlmMoveToStepRequest extends RequestBase {
   index: IndexName
   body?: {
-    current_step?: IlmMoveToStepStepKey
-    next_step?: IlmMoveToStepStepKey
+    current_step: IlmMoveToStepStepKey
+    next_step: IlmMoveToStepStepKey
   }
 }
 
 export type IlmMoveToStepResponse = AcknowledgedResponseBase
 
 export interface IlmMoveToStepStepKey {
-  action: string
-  name: string
+  action?: string
+  name?: string
   phase: string
 }
 
@@ -10582,6 +10582,7 @@ export interface IndicesDataStreamTimestampField {
 
 export interface IndicesDataStreamVisibility {
   hidden?: boolean
+  allow_custom_routing?: boolean
 }
 
 export interface IndicesDownsampleConfig {
diff --git a/specification/_types/Base.ts b/specification/_types/Base.ts
index 2ac27fe0c5..383dab96b3 100644
--- a/specification/_types/Base.ts
+++ b/specification/_types/Base.ts
@@ -89,7 +89,8 @@ export class IndicesResponseBase extends AcknowledgedResponseBase {
 }
 
 export class ShardsOperationResponseBase {
-  _shards: ShardStatistics
+  // _shards is always returned, but not when wait_for_completion is false in the request
+  _shards?: ShardStatistics
 }
 
 export class CustomResponseBuilderBase {}
diff --git a/specification/ilm/move_to_step/MoveToStepRequest.ts b/specification/ilm/move_to_step/MoveToStepRequest.ts
index 3005e5f99b..d2d5f305ea 100644
--- a/specification/ilm/move_to_step/MoveToStepRequest.ts
+++ b/specification/ilm/move_to_step/MoveToStepRequest.ts
@@ -30,7 +30,7 @@ export interface Request extends RequestBase {
     index: IndexName
   }
   body: {
-    current_step?: StepKey
-    next_step?: StepKey
+    current_step: StepKey
+    next_step: StepKey
   }
 }
diff --git a/specification/ilm/move_to_step/types.ts b/specification/ilm/move_to_step/types.ts
index 01d8fca691..f15c0df8fd 100644
--- a/specification/ilm/move_to_step/types.ts
+++ b/specification/ilm/move_to_step/types.ts
@@ -18,7 +18,8 @@
  */
 
 export class StepKey {
-  action: string
-  name: string
+  // action and name are optional in case they are used in next_step
+  action?: string
+  name?: string
   phase: string
 }
diff --git a/specification/indices/_types/DataStream.ts b/specification/indices/_types/DataStream.ts
index 77ebad5d13..444be72bf1 100644
--- a/specification/indices/_types/DataStream.ts
+++ b/specification/indices/_types/DataStream.ts
@@ -143,4 +143,5 @@ export class DataStreamIndex {
 
 export class DataStreamVisibility {
   hidden?: boolean
+  allow_custom_routing?: boolean
 }