diff --git a/keyserver/src/creators/thread-creator.js b/keyserver/src/creators/thread-creator.js
--- a/keyserver/src/creators/thread-creator.js
+++ b/keyserver/src/creators/thread-creator.js
@@ -192,7 +192,11 @@
     validateMembers: { initialMemberIDs, ghostMemberIDs },
   } = await promiseAll(checkPromises);
 
-  if (sourceMessage && sourceMessage.type === messageTypes.REACTION) {
+  if (
+    sourceMessage &&
+    (sourceMessage.type === messageTypes.REACTION ||
+      sourceMessage.type === messageTypes.EDIT_MESSAGE)
+  ) {
     throw new ServerError('invalid_parameters');
   }
 
diff --git a/keyserver/src/fetchers/message-fetchers.js b/keyserver/src/fetchers/message-fetchers.js
--- a/keyserver/src/fetchers/message-fetchers.js
+++ b/keyserver/src/fetchers/message-fetchers.js
@@ -689,8 +689,9 @@
     if (rawMessageInfo.id) {
       invariant(
         rawMessageInfo.type !== messageTypes.SIDEBAR_SOURCE &&
-          rawMessageInfo.type !== messageTypes.REACTION,
-        'SIDEBAR_SOURCE should not point to a SIDEBAR_SOURCE or REACTION',
+          rawMessageInfo.type !== messageTypes.REACTION &&
+          rawMessageInfo.type !== messageTypes.EDIT_MESSAGE,
+        'SIDEBAR_SOURCE should not point to a SIDEBAR_SOURCE, REACTION or EDIT_MESSAGE',
       );
       messagesByID.set(rawMessageInfo.id, rawMessageInfo);
     }
diff --git a/lib/selectors/chat-selectors.js b/lib/selectors/chat-selectors.js
--- a/lib/selectors/chat-selectors.js
+++ b/lib/selectors/chat-selectors.js
@@ -372,7 +372,10 @@
   for (let i = messages.length - 1; i >= 0; i--) {
     const messageInfo = messages[i];
 
-    if (messageInfo.type === messageTypes.REACTION) {
+    if (
+      messageInfo.type === messageTypes.REACTION ||
+      messageInfo.type === messageTypes.EDIT_MESSAGE
+    ) {
       continue;
     }
 
diff --git a/lib/shared/message-utils.js b/lib/shared/message-utils.js
--- a/lib/shared/message-utils.js
+++ b/lib/shared/message-utils.js
@@ -28,6 +28,10 @@
   type RawComposableMessageInfo,
   type ThreadMessageInfo,
 } from '../types/message-types.js';
+import type {
+  EditMessageInfo,
+  RawEditMessageInfo,
+} from '../types/messages/edit.js';
 import type { ImagesMessageData } from '../types/messages/images.js';
 import type { MediaMessageData } from '../types/messages/media.js';
 import type {
@@ -313,7 +317,10 @@
 }
 
 function stripLocalID(
-  rawMessageInfo: RawComposableMessageInfo | RawReactionMessageInfo,
+  rawMessageInfo:
+    | RawComposableMessageInfo
+    | RawReactionMessageInfo
+    | RawEditMessageInfo,
 ) {
   const { localID, ...rest } = rawMessageInfo;
   return rest;
@@ -367,7 +374,8 @@
   messageInfo:
     | ComposableMessageInfo
     | RobotextMessageInfo
-    | ReactionMessageInfo,
+    | ReactionMessageInfo
+    | EditMessageInfo,
   threadInfo: ThreadInfo,
   markdownRules: ParserRules,
 ): EntityText {
@@ -380,7 +388,8 @@
     messageInfo.type !== messageTypes.TEXT &&
       messageInfo.type !== messageTypes.IMAGES &&
       messageInfo.type !== messageTypes.MULTIMEDIA &&
-      messageInfo.type !== messageTypes.REACTION,
+      messageInfo.type !== messageTypes.REACTION &&
+      messageInfo.type !== messageTypes.EDIT_MESSAGE,
     'messageTitle can only be auto-generated for RobotextMessageInfo',
   );
   return robotextForMessageInfo(messageInfo, threadInfo);
diff --git a/lib/shared/messages/sidebar-source-message-spec.js b/lib/shared/messages/sidebar-source-message-spec.js
--- a/lib/shared/messages/sidebar-source-message-spec.js
+++ b/lib/shared/messages/sidebar-source-message-spec.js
@@ -108,8 +108,9 @@
     invariant(
       sourceMessage &&
         sourceMessage.type !== messageTypes.SIDEBAR_SOURCE &&
-        sourceMessage.type !== messageTypes.REACTION,
-      'Sidebars can not be created from SIDEBAR SOURCE OR REACTION',
+        sourceMessage.type !== messageTypes.REACTION &&
+        sourceMessage.type !== messageTypes.EDIT_MESSAGE,
+      'Sidebars can not be created from SIDEBAR SOURCE, REACTION or EDIT MESSAGE',
     );
 
     return {
diff --git a/lib/types/message-types.js b/lib/types/message-types.js
--- a/lib/types/message-types.js
+++ b/lib/types/message-types.js
@@ -48,6 +48,11 @@
   EditEntryMessageInfo,
   RawEditEntryMessageInfo,
 } from './messages/edit-entry.js';
+import type {
+  RawEditMessageInfo,
+  EditMessageData,
+  EditMessageInfo,
+} from './messages/edit.js';
 import type {
   ImagesMessageData,
   ImagesMessageInfo,
@@ -131,6 +136,7 @@
   // Appears in the newly created sidebar
   CREATE_SIDEBAR: 18,
   REACTION: 19,
+  EDIT_MESSAGE: 20,
 });
 export type MessageType = $Values<typeof messageTypes>;
 export function assertMessageType(ourMessageType: number): MessageType {
@@ -154,7 +160,8 @@
       ourMessageType === 16 ||
       ourMessageType === 17 ||
       ourMessageType === 18 ||
-      ourMessageType === 19,
+      ourMessageType === 19 ||
+      ourMessageType === 20,
     'number is not MessageType enum',
   );
   return ourMessageType;
@@ -245,7 +252,8 @@
   | UpdateRelationshipMessageData
   | SidebarSourceMessageData
   | CreateSidebarMessageData
-  | ReactionMessageData;
+  | ReactionMessageData
+  | EditMessageData;
 
 export type MultimediaMessageData = ImagesMessageData | MediaMessageData;
 
@@ -281,7 +289,8 @@
   | RawComposableMessageInfo
   | RawRobotextMessageInfo
   | RawSidebarSourceMessageInfo
-  | RawReactionMessageInfo;
+  | RawReactionMessageInfo
+  | RawEditMessageInfo;
 
 export type LocallyComposedMessageInfo =
   | ({
@@ -338,7 +347,8 @@
   | ComposableMessageInfo
   | RobotextMessageInfo
   | SidebarSourceMessageInfo
-  | ReactionMessageInfo;
+  | ReactionMessageInfo
+  | EditMessageInfo;
 
 export type ThreadMessageInfo = {
   messageIDs: string[],