diff --git a/lib/ops/create-replace-thread-operation.js b/lib/ops/create-replace-thread-operation.js
--- a/lib/ops/create-replace-thread-operation.js
+++ b/lib/ops/create-replace-thread-operation.js
@@ -1,7 +1,7 @@
 // @flow
 
 import type { ReplaceThreadOperation } from './thread-store-ops.js';
-import { threadSpecs } from '../shared/threads/thread-specs.js';
+import { getDataIsBackedUpByThread } from '../shared/threads/protocols/thread-protocols.js';
 import type { RawThreadInfo } from '../types/minimally-encoded-thread-permissions-types.js';
 
 function createReplaceThreadOperation(
@@ -13,7 +13,7 @@
     payload: {
       id,
       threadInfo,
-      isBackedUp: threadSpecs[threadInfo.type].protocol.dataIsBackedUp,
+      isBackedUp: getDataIsBackedUpByThread(id, threadInfo),
     },
   };
 }
diff --git a/lib/ops/entries-store-ops.js b/lib/ops/entries-store-ops.js
--- a/lib/ops/entries-store-ops.js
+++ b/lib/ops/entries-store-ops.js
@@ -2,7 +2,7 @@
 
 import type { BaseStoreOpsHandlers } from './base-ops.js';
 import { daysToEntriesFromEntryInfos } from '../reducers/entry-reducer.js';
-import { threadSpecs } from '../shared/threads/thread-specs.js';
+import { getDataIsBackedUpByThread } from '../shared/threads/protocols/thread-protocols.js';
 import type {
   EntryStore,
   RawEntryInfo,
@@ -141,18 +141,12 @@
   threadInfos: RawThreadInfos,
 ): ReplaceEntryOperation {
   const threadInfo = threadInfos[entry.threadID];
-  if (!threadInfo) {
-    return {
-      type: 'replace_entry',
-      payload: { id, entry, isBackedUp: true },
-    };
-  }
   return {
     type: 'replace_entry',
     payload: {
       id,
       entry,
-      isBackedUp: threadSpecs[threadInfo.type].protocol.dataIsBackedUp,
+      isBackedUp: getDataIsBackedUpByThread(entry.threadID, threadInfo),
     },
   };
 }
diff --git a/lib/ops/message-store-ops.js b/lib/ops/message-store-ops.js
--- a/lib/ops/message-store-ops.js
+++ b/lib/ops/message-store-ops.js
@@ -1,7 +1,7 @@
 // @flow
 
 import { type BaseStoreOpsHandlers } from './base-ops.js';
-import { threadSpecs } from '../shared/threads/thread-specs.js';
+import { getDataIsBackedUpByThread } from '../shared/threads/protocols/thread-protocols.js';
 import type {
   ClientDBMessageInfo,
   ClientDBThreadMessageInfo,
@@ -265,18 +265,12 @@
   threadInfos: MixedRawThreadInfos,
 ): ReplaceMessageOperation {
   const threadInfo = threadInfos[messageInfo.threadID];
-  if (!threadInfo) {
-    return {
-      type: 'replace',
-      payload: { id, messageInfo, isBackedUp: true },
-    };
-  }
   return {
     type: 'replace',
     payload: {
       id,
       messageInfo,
-      isBackedUp: threadSpecs[threadInfo.type].protocol.dataIsBackedUp,
+      isBackedUp: getDataIsBackedUpByThread(messageInfo.threadID, threadInfo),
     },
   };
 }
@@ -289,7 +283,7 @@
   let notBackedUpThreads: MessageStoreThreads = {};
   for (const threadID in threads) {
     const threadInfo = threadInfos[threadID];
-    if (!threadInfo || threadSpecs[threadInfo.type].protocol.dataIsBackedUp) {
+    if (getDataIsBackedUpByThread(threadID, threadInfo)) {
       backedUpThreads = {
         ...backedUpThreads,
         [threadID]: threads[threadID],
diff --git a/lib/ops/thread-activity-store-ops.js b/lib/ops/thread-activity-store-ops.js
--- a/lib/ops/thread-activity-store-ops.js
+++ b/lib/ops/thread-activity-store-ops.js
@@ -1,7 +1,7 @@
 // @flow
 
 import { type BaseStoreOpsHandlers } from './base-ops.js';
-import { threadSpecs } from '../shared/threads/thread-specs.js';
+import { getDataIsBackedUpByThread } from '../shared/threads/protocols/thread-protocols.js';
 import type {
   ThreadActivityStore,
   ThreadActivityStoreEntry,
@@ -144,18 +144,12 @@
   threadInfos: RawThreadInfos,
 ): ReplaceThreadActivityEntryOperation {
   const threadInfo = threadInfos[id];
-  if (!threadInfo) {
-    return {
-      type: 'replace_thread_activity_entry',
-      payload: { id, threadActivityStoreEntry, isBackedUp: true },
-    };
-  }
   return {
     type: 'replace_thread_activity_entry',
     payload: {
       id,
       threadActivityStoreEntry,
-      isBackedUp: threadSpecs[threadInfo.type].protocol.dataIsBackedUp,
+      isBackedUp: getDataIsBackedUpByThread(id, threadInfo),
     },
   };
 }
diff --git a/lib/shared/threads/protocols/thread-protocols.js b/lib/shared/threads/protocols/thread-protocols.js
--- a/lib/shared/threads/protocols/thread-protocols.js
+++ b/lib/shared/threads/protocols/thread-protocols.js
@@ -2,7 +2,10 @@
 
 import { dmThreadProtocol } from './dm-thread-protocol.js';
 import { keyserverThreadProtocol } from './keyserver-thread-protocol.js';
-import type { ThreadProtocol } from '../thread-spec.js';
+import type { RawThreadInfo } from '../../../types/minimally-encoded-thread-permissions-types.js';
+import { type LegacyRawThreadInfo } from '../../../types/thread-types.js';
+import { type ThreadProtocol } from '../thread-spec.js';
+import { threadSpecs } from '../thread-specs.js';
 
 const protocols = (): $ReadOnlyArray<ThreadProtocol<any>> => [
   dmThreadProtocol,
@@ -13,4 +16,14 @@
   return protocols().find(p => p.threadIDMatchesProtocol(threadID));
 }
 
-export { protocols, getProtocolByThreadID };
+function getDataIsBackedUpByThread(
+  threadID: string,
+  threadInfo: ?(LegacyRawThreadInfo | RawThreadInfo),
+): boolean {
+  if (threadInfo) {
+    return threadSpecs[threadInfo.type].protocol.dataIsBackedUp;
+  }
+  return !!getProtocolByThreadID(threadID)?.dataIsBackedUp;
+}
+
+export { protocols, getProtocolByThreadID, getDataIsBackedUpByThread };