diff --git a/spec/openapi.yaml b/spec/openapi.yaml
index c7d6dc6..42bde33 100644
--- a/spec/openapi.yaml
+++ b/spec/openapi.yaml
@@ -6170,6 +6170,14 @@ components:
           description: Filter results by source address.
           type: string
           example: "+61555555555"
+        sources:
+          description: Filter results by multiple source addresses. This property overrides the `source` parameter.
+          type: array
+          items:
+            type: string
+          example:
+            - "+61555555555"
+            - "+614987654321"
         destination:
           description: Filter results by destination address.
           type: string
@@ -6430,10 +6438,26 @@ components:
           description: Filter results by source address.
           type: string
           example: "+61555555555"
+        sources:
+          description: Filter results by multiple source addresses. This property overrides the `source` parameter.
+          type: array
+          items:
+            type: string
+          example:
+            - "+61555555555"
+            - "+614987654321"
         destination:
           description: Filter results by destination address.
           type: string
           example: "+61555555555"
+        destinations:
+          description: Filter results by multiple destination addresses. This property overrides the `destination` parameter.
+          type: array
+          items:
+            type: string
+          example:
+            - "+61555555555"
+            - "+614987654321"
         metadata_key:
           description: Filter results for messages that include a metadata key.
           type: string
@@ -7605,6 +7629,11 @@ components:
           type: number
           description: The amount of messages received
           example: 1
+        billing_category:
+          # TODO: Update docs on 5/Mar/2027 once 13 months of data are available.
+          type: string
+          description: The billing category applied to this RCS message (e.g. RCS_BASIC, RCS_SINGLE, RCS_RICH, RCS_RICH_MEDIA). Supported from 5/Feb/2026. This field is only available for RCS messages and only for messages sent on or after this date.
+          example: RCS_BASIC
         message_type:
           $ref: '#/components/schemas/RichMessageType'
         metadata: