diff --git a/lib/reducers/local-id-reducer.js b/lib/reducers/local-id-reducer.js
--- a/lib/reducers/local-id-reducer.js
+++ b/lib/reducers/local-id-reducer.js
@@ -17,6 +17,7 @@
   numberFromLocalID,
   highestLocalIDSelector,
 } from '../selectors/local-id-selectors.js';
+import { updateSpecs } from '../shared/updates/update-specs.js';
 import type { RawMessageInfo } from '../types/message-types.js';
 import type { BaseAction } from '../types/redux-types.js';
 import { rehydrateActionType } from '../types/redux-types.js';
@@ -24,7 +25,6 @@
   fullStateSyncActionType,
   incrementalStateSyncActionType,
 } from '../types/socket-types.js';
-import { updateTypes } from '../types/update-types-enum.js';
 import {
   type ClientUpdateInfo,
   processUpdatesActionType,
@@ -112,14 +112,8 @@
 function getRawMessageInfosFromUpdates(
   updates: $ReadOnlyArray<ClientUpdateInfo>,
 ): RawMessageInfo[] {
-  const rawMessageInfos = [];
-  for (const updateInfo of updates) {
-    if (updateInfo.type !== updateTypes.JOIN_THREAD) {
-      continue;
-    }
-    for (const messageInfo of updateInfo.rawMessageInfos) {
-      rawMessageInfos.push(messageInfo);
-    }
-  }
-  return rawMessageInfos;
+  return updates
+    .map(update => updateSpecs[update.type].getRawMessageInfos?.(update))
+    .filter(Boolean)
+    .flat();
 }
diff --git a/lib/shared/updates/join-thread-spec.js b/lib/shared/updates/join-thread-spec.js
--- a/lib/shared/updates/join-thread-spec.js
+++ b/lib/shared/updates/join-thread-spec.js
@@ -52,4 +52,7 @@
     }
     return new Set([...filteredThreadIDs, update.threadInfo.id]);
   },
+  getRawMessageInfos(update: ThreadJoinUpdateInfo) {
+    return update.rawMessageInfos;
+  },
 });
diff --git a/lib/shared/updates/update-spec.js b/lib/shared/updates/update-spec.js
--- a/lib/shared/updates/update-spec.js
+++ b/lib/shared/updates/update-spec.js
@@ -2,6 +2,7 @@
 
 import type { ThreadStoreOperation } from '../../ops/thread-store-ops.js';
 import type { RawEntryInfo } from '../../types/entry-types.js';
+import type { RawMessageInfo } from '../../types/message-types.js';
 import type { RawThreadInfos } from '../../types/thread-types.js';
 import type { ClientUpdateInfo } from '../../types/update-types.js';
 import type { CurrentUserInfo, UserInfos } from '../../types/user-types.js';
@@ -25,4 +26,5 @@
     filteredThreadIDs: $ReadOnlySet<string>,
     update: UpdateInfo,
   ) => $ReadOnlySet<string>,
+  +getRawMessageInfos?: (update: UpdateInfo) => $ReadOnlyArray<RawMessageInfo>,
 };