diff --git a/lib/shared/messages/sidebar-source-message-spec.js b/lib/shared/messages/sidebar-source-message-spec.js
index 9f52d1811..d0ae9de21 100644
--- a/lib/shared/messages/sidebar-source-message-spec.js
+++ b/lib/shared/messages/sidebar-source-message-spec.js
@@ -1,110 +1,111 @@
 // @flow
 
 import invariant from 'invariant';
 
 import type {
   RawSidebarSourceMessageInfo,
   SidebarSourceMessageData,
   SidebarSourceMessageInfo,
 } from '../../types/message-types';
 import { messageTypes } from '../../types/message-types';
 import { hasMinCodeVersion } from '../version-utils';
 import type { MessageSpec } from './message-spec';
 import { assertSingleMessageInfo } from './utils';
 
 export const sidebarSourceMessageSpec: MessageSpec<
   SidebarSourceMessageData,
   RawSidebarSourceMessageInfo,
   SidebarSourceMessageInfo,
 > = Object.freeze({
   messageContent(data) {
     const sourceMessageID = data.sourceMessage?.id;
     invariant(sourceMessageID, 'Source message id should be set');
     return JSON.stringify({
       sourceMessageID,
     });
   },
 
   rawMessageInfoFromRow(row, params) {
     const { derivedMessages } = params;
     invariant(derivedMessages, 'Derived messages should be provided');
 
     const content = JSON.parse(row.content);
     const sourceMessage = derivedMessages.get(content.sourceMessageID);
     if (!sourceMessage) {
       console.warn(
         `Message with id ${row.id} has a derived message ` +
           `${content.sourceMessageID} which is not present in the database`,
       );
     }
     return {
       type: messageTypes.SIDEBAR_SOURCE,
       id: row.id.toString(),
       threadID: row.threadID.toString(),
       time: row.time,
       creatorID: row.creatorID.toString(),
       sourceMessage,
     };
   },
 
   createMessageInfo(rawMessageInfo, creator, params) {
     if (!rawMessageInfo.sourceMessage) {
       return null;
     }
     const sourceMessage = params.createMessageInfoFromRaw(
       rawMessageInfo.sourceMessage,
     );
     invariant(
       sourceMessage && sourceMessage.type !== messageTypes.SIDEBAR_SOURCE,
       'Sidebars can not be created from SIDEBAR SOURCE',
     );
 
     return {
       type: messageTypes.SIDEBAR_SOURCE,
       id: rawMessageInfo.id,
       threadID: rawMessageInfo.threadID,
       creator,
       time: rawMessageInfo.time,
       sourceMessage,
     };
   },
 
   rawMessageInfoFromMessageData(messageData, id) {
     return { ...messageData, id };
   },
 
   shimUnsupportedMessageInfo(rawMessageInfo, platformDetails) {
     // TODO determine min code version
     if (
       hasMinCodeVersion(platformDetails, 75) &&
       rawMessageInfo.sourceMessage
     ) {
       return rawMessageInfo;
     }
     const { id } = rawMessageInfo;
     invariant(id !== null && id !== undefined, 'id should be set on server');
     return {
       type: messageTypes.UNSUPPORTED,
       id,
       threadID: rawMessageInfo.threadID,
       creatorID: rawMessageInfo.creatorID,
       time: rawMessageInfo.time,
       robotext: 'first message in sidebar',
+      dontPrefixCreator: true,
       unsupportedMessageInfo: rawMessageInfo,
     };
   },
 
   notificationTexts(messageInfos, threadInfo, params) {
     const messageInfo = assertSingleMessageInfo(messageInfos);
     invariant(
       messageInfo.type === messageTypes.SIDEBAR_SOURCE,
       'messageInfo should be messageTypes.SIDEBAR_SOURCE!',
     );
     const sourceMessageInfo = messageInfo.sourceMessage;
     return params.notificationTexts([sourceMessageInfo], threadInfo);
   },
 
   generatesNotifs: false,
 
   startsThread: true,
 });
diff --git a/lib/shared/messages/unsupported-message-spec.js b/lib/shared/messages/unsupported-message-spec.js
index cbaa431d1..9ab1c035b 100644
--- a/lib/shared/messages/unsupported-message-spec.js
+++ b/lib/shared/messages/unsupported-message-spec.js
@@ -1,32 +1,36 @@
 // @flow
 
 import { messageTypes } from '../../types/message-types';
 import type {
   RawUnsupportedMessageInfo,
   UnsupportedMessageInfo,
 } from '../../types/message/unsupported';
 import type { MessageSpec } from './message-spec';
 
 export const unsupportedMessageSpec: MessageSpec<
   null,
   RawUnsupportedMessageInfo,
   UnsupportedMessageInfo,
 > = Object.freeze({
   createMessageInfo(rawMessageInfo, creator) {
     return {
       type: messageTypes.UNSUPPORTED,
       id: rawMessageInfo.id,
       threadID: rawMessageInfo.threadID,
       creator,
       time: rawMessageInfo.time,
       robotext: rawMessageInfo.robotext,
+      dontPrefixCreator: rawMessageInfo.dontPrefixCreator,
       unsupportedMessageInfo: rawMessageInfo.unsupportedMessageInfo,
     };
   },
 
   robotext(messageInfo, creator) {
+    if (messageInfo.dontPrefixCreator) {
+      return messageInfo.robotext;
+    }
     return `${creator} ${messageInfo.robotext}`;
   },
 
   generatesNotifs: true,
 });
diff --git a/lib/types/message/unsupported.js b/lib/types/message/unsupported.js
index c195ae392..18e6007a1 100644
--- a/lib/types/message/unsupported.js
+++ b/lib/types/message/unsupported.js
@@ -1,23 +1,25 @@
 // @flow
 
 import type { RelativeUserInfo } from '../user-types';
 
 export type RawUnsupportedMessageInfo = {|
   type: 13,
   id: string,
   threadID: string,
   creatorID: string,
   time: number,
   robotext: string,
+  dontPrefixCreator?: boolean,
   unsupportedMessageInfo: Object,
 |};
 
 export type UnsupportedMessageInfo = {|
   type: 13,
   id: string,
   threadID: string,
   creator: RelativeUserInfo,
   time: number,
   robotext: string,
+  dontPrefixCreator?: boolean,
   unsupportedMessageInfo: Object,
 |};