diff --git a/lib/shared/redux/client-db-utils.js b/lib/shared/redux/client-db-utils.js
new file mode 100644
--- /dev/null
+++ b/lib/shared/redux/client-db-utils.js
@@ -0,0 +1,57 @@
+// @flow
+
+import _keyBy from 'lodash/fp/keyBy.js';
+
+import {
+  threadStoreOpsHandlers,
+  type ClientDBThreadStoreOperation,
+  type ReplaceThreadOperation,
+  type ThreadStoreOperation,
+} from '../../ops/thread-store-ops.js';
+import type { RawThreadInfos, ThreadStore } from '../../types/thread-types.js';
+import { entries } from '../../utils/objects.js';
+
+function updateThreadStoreThreadInfos(
+  threadStore: ThreadStore,
+  migrationFunc: RawThreadInfos => RawThreadInfos,
+): {
+  +newThreadStore: ThreadStore,
+  +dbOperations: $ReadOnlyArray<ClientDBThreadStoreOperation>,
+} {
+  const rawThreadInfos = threadStore.threadInfos;
+
+  // 1. Convert `RawThreadInfo`s to a map of `threadID` => `threadInfo`.
+  const keyedRawThreadInfos = _keyBy('id')(rawThreadInfos);
+
+  // 2. Apply `migrationFunc` to `ThreadInfo`s.
+  const updatedKeyedRawThreadInfos = migrationFunc(keyedRawThreadInfos);
+
+  // 3. Construct `replace` `ThreadStoreOperation`s.
+  const replaceOps: $ReadOnlyArray<ReplaceThreadOperation> = entries(
+    updatedKeyedRawThreadInfos,
+  ).map(([id, threadInfo]) => ({
+    type: 'replace',
+    payload: { id, threadInfo },
+  }));
+
+  // 4. Prepend `replaceOps` with `remove_all` ops
+  const operations: $ReadOnlyArray<ThreadStoreOperation> = [
+    { type: 'remove_all' },
+    ...replaceOps,
+  ];
+
+  // 5. Process `ThreadStoreOperation`s to get new `ThreadStore`.
+  const newThreadStore: ThreadStore =
+    threadStoreOpsHandlers.processStoreOperations(threadStore, operations);
+
+  // 6. Convert `ThreadStoreOperation`s to `ClientDBThreadStoreOperation`s.
+  const dbOperations: $ReadOnlyArray<ClientDBThreadStoreOperation> =
+    threadStoreOpsHandlers.convertOpsToClientDBOps(operations);
+
+  return {
+    newThreadStore,
+    dbOperations,
+  };
+}
+
+export { updateThreadStoreThreadInfos };