diff --git a/web/redux/persist.js b/web/redux/persist.js
--- a/web/redux/persist.js
+++ b/web/redux/persist.js
@@ -48,6 +48,7 @@
 } from './handle-redux-migration-failure.js';
 import { rootKey, rootKeyPrefix } from './persist-constants.js';
 import type { AppState } from './redux-setup.js';
+import { unshimClientDB } from './unshim-utils.js';
 import { authoritativeKeyserverID } from '../authoritative-keyserver.js';
 import { getCommSharedWorker } from '../shared-worker/shared-worker-provider.js';
 import { getOlmWasmPath } from '../shared-worker/utils/constants.js';
@@ -467,6 +468,8 @@
 
     return state;
   },
+  [18]: (state: AppState) =>
+    unshimClientDB(state, [messageTypes.UPDATE_RELATIONSHIP]),
 };
 
 const migrateStorageToSQLite: StorageMigrationFunction = async debug => {
diff --git a/web/redux/unshim-utils.js b/web/redux/unshim-utils.js
new file mode 100644
--- /dev/null
+++ b/web/redux/unshim-utils.js
@@ -0,0 +1,96 @@
+// @flow
+
+import {
+  type MessageStoreOperation,
+  messageStoreOpsHandlers,
+} from 'lib/ops/message-store-ops.js';
+import { messageID } from 'lib/shared/message-utils.js';
+import { unshimFunc } from 'lib/shared/unshim-utils.js';
+import { type MessageType } from 'lib/types/message-types-enum.js';
+import type {
+  RawMessageInfo,
+  ClientDBMessageInfo,
+} from 'lib/types/message-types.js';
+import { translateClientDBMessageInfoToRawMessageInfo } from 'lib/utils/message-ops-utils.js';
+
+import { handleReduxMigrationFailure } from './handle-redux-migration-failure.js';
+import type { AppState } from './redux-setup.js';
+import { getCommSharedWorker } from '../shared-worker/shared-worker-provider.js';
+import { workerRequestMessageTypes } from '../types/worker-types.js';
+
+const {
+  processStoreOperations: processMessageStoreOperations,
+  convertOpsToClientDBOps: convertMessageOpsToClientDBOps,
+} = messageStoreOpsHandlers;
+
+async function unshimClientDB(
+  state: AppState,
+  unshimTypes: $ReadOnlyArray<MessageType>,
+): Promise<AppState> {
+  // 1. Check if `databaseModule` is supported and early-exit if not.
+  const sharedWorker = await getCommSharedWorker();
+  const isDatabaseSupported = await sharedWorker.isSupported();
+
+  if (!isDatabaseSupported) {
+    return state;
+  }
+
+  // 2. Get existing `stores` from SQLite.
+  const stores = await sharedWorker.schedule({
+    type: workerRequestMessageTypes.GET_CLIENT_STORE,
+  });
+
+  const messages: ?$ReadOnlyArray<ClientDBMessageInfo> =
+    stores?.store?.messages;
+
+  if (messages === null || messages === undefined || messages.length === 0) {
+    return state;
+  }
+
+  // 3. Translate `ClientDBMessageInfo`s to `RawMessageInfo`s.
+  const rawMessageInfos = messages.map(
+    translateClientDBMessageInfoToRawMessageInfo,
+  );
+
+  // 4. "Unshim" translated `RawMessageInfo`s.
+  const unshimmedRawMessageInfos = rawMessageInfos.map(messageInfo =>
+    unshimFunc(messageInfo, new Set(unshimTypes)),
+  );
+
+  // 5. Construct `MessageStoreOperation`s to clear SQLite `messages` table and
+  //    repopulate with unshimmed `RawMessageInfo`s.
+  const operations: $ReadOnlyArray<MessageStoreOperation> = [
+    {
+      type: 'remove_all',
+    },
+    ...unshimmedRawMessageInfos.map((message: RawMessageInfo) => ({
+      type: 'replace',
+      payload: { id: messageID(message), messageInfo: message },
+    })),
+  ];
+
+  // 6. Process the constructed `messageStoreOperations`.
+  try {
+    const convertedMessageStoreOperations =
+      convertMessageOpsToClientDBOps(operations);
+    await sharedWorker.schedule({
+      type: workerRequestMessageTypes.PROCESS_STORE_OPERATIONS,
+      storeOperations: {
+        messageStoreOperations: convertedMessageStoreOperations,
+      },
+    });
+    const processedMessageStore = processMessageStoreOperations(
+      state.messageStore,
+      operations,
+    );
+    return {
+      ...state,
+      messageStore: processedMessageStore,
+    };
+  } catch (e) {
+    console.log(e);
+    return handleReduxMigrationFailure(state);
+  }
+}
+
+export { unshimClientDB };