diff --git a/apify-api/openapi/components/schemas/actors/TaggedBuildInfo.yaml b/apify-api/openapi/components/schemas/actors/TaggedBuildInfo.yaml
index 08dfe5dae5..dc1ef70c40 100644
--- a/apify-api/openapi/components/schemas/actors/TaggedBuildInfo.yaml
+++ b/apify-api/openapi/components/schemas/actors/TaggedBuildInfo.yaml
@@ -7,9 +7,9 @@ properties:
     description: The ID of the build associated with this tag.
     examples: [z2EryhbfhgSyqj6Hn]
   buildNumber:
-    type: string
+    type: [string, "null"]
     pattern: ^([0-9]|[1-9][0-9])\.([0-9]|[1-9][0-9])(\.[1-9][0-9]{0,4})$
-    description: The build number/version string.
+    description: The build number/version string. Can be `null` for legacy builds that lack a valid build number.
     examples: [0.0.2]
   buildNumberInt:
     type: integer
diff --git a/apify-api/openapi/components/schemas/common/ErrorType.yaml b/apify-api/openapi/components/schemas/common/ErrorType.yaml
index efc6eb64be..1d5a155c21 100644
--- a/apify-api/openapi/components/schemas/common/ErrorType.yaml
+++ b/apify-api/openapi/components/schemas/common/ErrorType.yaml
@@ -65,6 +65,7 @@ enum:
   - cannot-metamorph-to-pay-per-result-actor
   - cannot-modify-actor-pricing-too-frequently
   - cannot-modify-actor-pricing-with-immediate-effect
+  - cannot-monetize-without-payout-billing-info
   - cannot-override-paid-actor-trial
   - cannot-permanently-delete-subscription
   - cannot-publish-actor
diff --git a/apify-api/openapi/paths/actor-tasks/actor-tasks.yaml b/apify-api/openapi/paths/actor-tasks/actor-tasks.yaml
index a6b7a0d6a4..a06d64cf63 100644
--- a/apify-api/openapi/paths/actor-tasks/actor-tasks.yaml
+++ b/apify-api/openapi/paths/actor-tasks/actor-tasks.yaml
@@ -139,6 +139,8 @@ post:
       $ref: ../../components/responses/Unauthorized.yaml
     "403":
       $ref: ../../components/responses/Forbidden.yaml
+    "404":
+      $ref: ../../components/responses/NotFound.yaml
     "405":
       $ref: ../../components/responses/MethodNotAllowed.yaml
     "409":
diff --git a/apify-api/openapi/paths/actor-tasks/actor-tasks@{actorTaskId}.yaml b/apify-api/openapi/paths/actor-tasks/actor-tasks@{actorTaskId}.yaml
index 5b97dab2b4..4b2d8acde8 100644
--- a/apify-api/openapi/paths/actor-tasks/actor-tasks@{actorTaskId}.yaml
+++ b/apify-api/openapi/paths/actor-tasks/actor-tasks@{actorTaskId}.yaml
@@ -101,6 +101,8 @@ put:
       $ref: ../../components/responses/NotFound.yaml
     "405":
       $ref: ../../components/responses/MethodNotAllowed.yaml
+    "409":
+      $ref: ../../components/responses/Conflict.yaml
     "413":
       $ref: ../../components/responses/PayloadTooLarge.yaml
     "415":
diff --git a/apify-api/openapi/paths/actors/acts@{actorId}@builds.yaml b/apify-api/openapi/paths/actors/acts@{actorId}@builds.yaml
index c8381cf0d6..5ee8b191f8 100644
--- a/apify-api/openapi/paths/actors/acts@{actorId}@builds.yaml
+++ b/apify-api/openapi/paths/actors/acts@{actorId}@builds.yaml
@@ -120,6 +120,8 @@ post:
       $ref: ../../components/responses/BadRequest.yaml
     "401":
       $ref: ../../components/responses/Unauthorized.yaml
+    "402":
+      $ref: ../../components/responses/PaymentRequired.yaml
     "403":
       $ref: ../../components/responses/Forbidden.yaml
     "404":