diff --git a/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json b/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
index 738e6472171e..ccbff6064853 100644
--- a/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
+++ b/specification/eventgrid/data-plane/Microsoft.Communication/stable/2018-01-01/AzureCommunicationServices.json
@@ -21,6 +21,20 @@
         }
       }
     },
+    "AcsChatMessageReceivedInThreadEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatMessageReceivedInThread event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatMessageEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "messageBody": {
+          "description": "The body of the chat message",
+          "type": "string"
+        }
+      }
+    },
     "AcsChatMessageEditedEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatMessageEdited event.",
       "allOf": [
@@ -40,6 +54,25 @@
         }
       }
     },
+    "AcsChatMessageEditedInThreadEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatMessageEditedInThread event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatMessageEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "messageBody": {
+          "description": "The body of the chat message",
+          "type": "string"
+        },
+        "editTime": {
+          "description": "The time at which the message was edited",
+          "format": "date-time",
+          "type": "string"
+        }
+      }
+    },
     "AcsChatMessageDeletedEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatMessageDeleted event.",
       "allOf": [
@@ -55,6 +88,21 @@
         }
       }
     },
+    "AcsChatMessageDeletedInThreadEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatMessageDeletedInThread event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatMessageEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "deleteTime": {
+          "description": "The time at which the message was deleted",
+          "format": "date-time",
+          "type": "string"
+        }
+      }
+    },
     "AcsChatThreadCreatedWithUserEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatThreadCreatedWithUser event.",
       "allOf": [
@@ -83,6 +131,34 @@
         }
       }
     },
+    "AcsChatThreadCreatedEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatThreadCreatedWithUser event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatThreadEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "createdByCommunicationIdentifier": {
+          "description": "The communication identifier of the user who created the thread",
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        },
+        "properties": {
+          "description": "The thread properties",
+          "type": "object",
+          "additionalProperties": {
+            "type": "object"
+          }
+        },
+        "participants": {
+          "description": "The list of properties of participants who are part of the thread",
+          "type": "array",
+          "items": {
+            "$ref": "#/definitions/AcsChatThreadParticipantProperties"
+          }
+        }
+      }
+    },
     "AcsChatThreadWithUserDeletedEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatThreadWithUserDeleted event.",
       "allOf": [
@@ -102,6 +178,25 @@
         }
       }
     },
+    "AcsChatThreadDeletedEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatThreadDeleted event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatThreadEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "deletedByCommunicationIdentifier": {
+          "description": "The communication identifier of the user who deleted the thread",
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        },
+        "deleteTime": {
+          "description": "The deletion time of the thread",
+          "format": "date-time",
+          "type": "string"
+        }
+      }
+    },
     "AcsChatThreadPropertiesUpdatedPerUserEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatThreadPropertiesUpdatedPerUser event.",
       "allOf": [
@@ -128,6 +223,32 @@
         }
       }
     },
+    "AcsChatThreadPropertiesUpdatedEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatThreadPropertiesUpdated event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatThreadEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "editedByCommunicationIdentifier": {
+          "description": "The communication identifier of the user who updated the thread properties",
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        },
+        "editTime": {
+          "description": "The time at which the properties of the thread were updated",
+          "format": "date-time",
+          "type": "string"
+        },
+        "properties": {
+          "description": "The updated thread properties",
+          "type": "object",
+          "additionalProperties": {
+            "type": "object"
+          }
+        }
+      }
+    },
     "AcsChatParticipantAddedToThreadWithUserEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatParticipantAddedToThreadWithUser event.",
       "allOf": [
@@ -174,6 +295,62 @@
         }
       }
     },
+    "AcsChatParticipantAddedToThreadEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatParticipantAddedToThread event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "time": {
+          "description": "The time at which the user was added to the thread",
+          "format": "date-time",
+          "type": "string"
+        },
+        "addedByCommunicationIdentifier": {
+          "description": "The communication identifier of the user who added the user",
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        },
+        "participantAdded": {
+          "description": "The details of the user who was added",
+          "$ref": "#/definitions/AcsChatThreadParticipantProperties"
+        },
+        "version": {
+          "description": "The version of the thread",
+          "type": "integer",
+          "format": "int64"
+        }
+      }
+    },
+    "AcsChatParticipantRemovedFromThreadEventData": {
+      "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.ChatParticipantRemovedFromThread event.",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "time": {
+          "description": "The time at which the user was removed to the thread",
+          "format": "date-time",
+          "type": "string"
+        },
+        "removedByCommunicationIdentifier": {
+          "description": "The communication identifier of the user who removed the user",
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        },
+        "participantRemoved": {
+          "description": "The details of the user who was removed",
+          "$ref": "#/definitions/AcsChatThreadParticipantProperties"
+        },
+        "version": {
+          "description": "The version of the thread",
+          "type": "integer",
+          "format": "int64"
+        }
+      }
+    },
     "AcsSmsDeliveryReportReceivedEventData": {
       "description": "Schema of the Data property of an EventGridEvent for an Microsoft.Communication.SMSDeliveryReportReceived event.",
       "allOf": [
@@ -243,6 +420,26 @@
         }
       }
     },
+    "AcsChatThreadEventInThreadBaseProperties": {
+      "description": "Schema of common properties of all chat thread events",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "createTime": {
+          "description": "The original creation time of the thread",
+          "format": "date-time",
+          "type": "string"
+        },
+        "version": {
+          "description": "The version of the thread",
+          "type": "integer",
+          "format": "int64"
+        }
+      }
+    },
     "AcsChatMessageEventBaseProperties": {
       "description": "Schema of common properties of all chat message events",
       "allOf": [
@@ -279,6 +476,52 @@
         }
       }
     },
+    "AcsChatMessageEventInThreadBaseProperties": {
+      "description": "Schema of common properties of all thread-level chat message events",
+      "allOf": [
+        {
+          "$ref": "#/definitions/AcsChatEventInThreadBaseProperties"
+        }
+      ],
+      "properties": {
+        "messageId": {
+          "description": "The chat message id",
+          "type": "string"
+        },
+        "senderCommunicationIdentifier": {
+          "description": "The communication identifier of the sender",
+          "$ref": "../../../../../communication/data-plane/Microsoft.CommunicationServicesCommon/stable/2021-03-07/common.json#/definitions/CommunicationIdentifierModel"
+        },
+        "senderDisplayName": {
+          "description": "The display name of the sender",
+          "type": "string"
+        },
+        "composeTime": {
+          "description": "The original compose time of the message",
+          "format": "date-time",
+          "type": "string"
+        },
+        "type": {
+          "description": "The type of the message",
+          "type": "string"
+        },
+        "version": {
+          "description": "The version of the message",
+          "type": "integer",
+          "format": "int64"
+        }
+      }
+    },
+    "AcsChatEventInThreadBaseProperties": {
+      "description": "Schema of common properties of all thread-level chat events",
+      "type": "object",
+      "properties": {
+        "threadId": {
+          "description": "The chat thread id",
+          "type": "string"
+        }
+      }
+    },
     "AcsChatEventBaseProperties": {
       "description": "Schema of common properties of all chat events",
       "type": "object",