diff --git a/lib/shared/messages/sidebar-source-message-spec.js b/lib/shared/messages/sidebar-source-message-spec.js
index 9d63a1e4e..10f2ee6f2 100644
--- a/lib/shared/messages/sidebar-source-message-spec.js
+++ b/lib/shared/messages/sidebar-source-message-spec.js
@@ -1,191 +1,164 @@
 // @flow
 
 import invariant from 'invariant';
 
 import {
   pushTypes,
   type CreateMessageInfoParams,
   type MessageSpec,
   type RawMessageInfoFromServerDBRowParams,
 } from './message-spec.js';
 import { joinResult } from './utils.js';
 import { messageTypes } from '../../types/message-types-enum.js';
 import {
   type RawSidebarSourceMessageInfo,
   type SidebarSourceMessageData,
   type SidebarSourceMessageInfo,
   type ClientDBMessageInfo,
   rawSidebarSourceMessageInfoValidator,
 } from '../../types/message-types.js';
-import type { RawUnsupportedMessageInfo } from '../../types/messages/unsupported.js';
 import type { NotifTexts } from '../../types/notif-types.js';
 import type { RelativeUserInfo } from '../../types/user-types.js';
 import { isInvalidSidebarSource } from '../message-utils.js';
 
 export const sidebarSourceMessageSpec: MessageSpec<
   SidebarSourceMessageData,
   RawSidebarSourceMessageInfo,
   SidebarSourceMessageInfo,
 > = Object.freeze({
   messageContentForServerDB(
     data: SidebarSourceMessageData | RawSidebarSourceMessageInfo,
   ): string {
     const sourceMessageID = data.sourceMessage?.id;
     invariant(sourceMessageID, 'Source message id should be set');
     return JSON.stringify({
       sourceMessageID,
     });
   },
 
   messageContentForClientDB(data: RawSidebarSourceMessageInfo): string {
     invariant(
       data.sourceMessage && data.sourceMessage.id,
       'sourceMessage and sourceMessage.id should be defined',
     );
     return JSON.stringify(data.sourceMessage);
   },
 
   rawMessageInfoFromClientDB(
     clientDBMessageInfo: ClientDBMessageInfo,
   ): RawSidebarSourceMessageInfo {
     invariant(
       clientDBMessageInfo.content !== undefined &&
         clientDBMessageInfo.content !== null,
       'content must be defined for SidebarSource',
     );
     const sourceMessage = JSON.parse(clientDBMessageInfo.content);
     const rawSidebarSourceMessageInfo: RawSidebarSourceMessageInfo = {
       type: messageTypes.SIDEBAR_SOURCE,
       id: clientDBMessageInfo.id,
       threadID: clientDBMessageInfo.thread,
       time: parseInt(clientDBMessageInfo.time),
       creatorID: clientDBMessageInfo.user,
       sourceMessage,
     };
     return rawSidebarSourceMessageInfo;
   },
 
   messageTitle() {
     invariant(false, 'Cannot call messageTitle on sidebarSourceMessageSpec');
   },
 
   rawMessageInfoFromServerDBRow(
     row: Object,
     params: RawMessageInfoFromServerDBRowParams,
   ): RawSidebarSourceMessageInfo {
     const { derivedMessages } = params;
     invariant(derivedMessages, 'Derived messages should be provided');
 
     const content = JSON.parse(row.content);
     let sourceMessage = derivedMessages.get(content.sourceMessageID);
     if (!sourceMessage || isInvalidSidebarSource(sourceMessage)) {
       console.warn(
         `Message with id ${row.id} has a derived message ` +
           `${content.sourceMessageID} which is not present in the database`,
       );
 
       sourceMessage = undefined;
     }
 
     return {
       type: messageTypes.SIDEBAR_SOURCE,
       id: row.id.toString(),
       threadID: row.threadID.toString(),
       time: row.time,
       creatorID: row.creatorID.toString(),
       sourceMessage,
     };
   },
 
   createMessageInfo(
     rawMessageInfo: RawSidebarSourceMessageInfo,
     creator: RelativeUserInfo,
     params: CreateMessageInfoParams,
   ): ?SidebarSourceMessageInfo {
     if (!rawMessageInfo.sourceMessage) {
       return null;
     }
     const sourceMessage = params.createMessageInfoFromRaw(
       rawMessageInfo.sourceMessage,
     );
     invariant(
       sourceMessage && !isInvalidSidebarSource(sourceMessage),
       'Sidebars can not be created from SIDEBAR SOURCE, REACTION, EDIT OR PIN MESSAGE',
     );
 
     return {
       type: messageTypes.SIDEBAR_SOURCE,
       id: rawMessageInfo.id,
       threadID: rawMessageInfo.threadID,
       creator,
       time: rawMessageInfo.time,
       sourceMessage,
     };
   },
 
   rawMessageInfoFromMessageData(
     messageData: SidebarSourceMessageData,
     id: ?string,
   ): RawSidebarSourceMessageInfo {
     invariant(id, 'RawSidebarSourceMessageInfo needs id');
     return { ...messageData, id };
   },
 
-  shimUnsupportedMessageInfo(
-    rawMessageInfo: RawSidebarSourceMessageInfo,
-  ): RawSidebarSourceMessageInfo | RawUnsupportedMessageInfo {
-    if (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 thread',
-      dontPrefixCreator: true,
-      unsupportedMessageInfo: rawMessageInfo,
-    };
-  },
-
-  unshimMessageInfo(
-    unwrapped: RawSidebarSourceMessageInfo,
-  ): RawSidebarSourceMessageInfo {
-    return unwrapped;
-  },
-
   notificationTexts(): Promise<NotifTexts> {
     invariant(
       false,
       'SIDEBAR_SOURCE notificationTexts should never be called directly!',
     );
   },
 
   notificationCollapseKey(rawMessageInfo: RawSidebarSourceMessageInfo): string {
     return joinResult(messageTypes.CREATE_SIDEBAR, rawMessageInfo.threadID);
   },
 
   generatesNotifs: async () => pushTypes.NOTIF,
 
   startsThread: true,
 
   canBeSidebarSource: false,
 
   canBePinned: false,
 
   parseDerivedMessages(row: Object, requiredIDs: Set<string>): void {
     try {
       const content = JSON.parse(row.content);
       requiredIDs.add(content.sourceMessageID);
     } catch (e) {
       console.error(
         `Error parsing content of message with id ${row.id}: ${e.message}`,
       );
     }
   },
 
   validator: rawSidebarSourceMessageInfoValidator,
 });