diff --git a/web/redux/persist-constants.js b/web/redux/persist-constants.js
--- a/web/redux/persist-constants.js
+++ b/web/redux/persist-constants.js
@@ -3,5 +3,6 @@
 const rootKey = 'root';
 const rootKeyPrefix = 'persist:';
 const completeRootKey = `${rootKeyPrefix}${rootKey}`;
+const storeVersion = 75;
 
-export { rootKey, rootKeyPrefix, completeRootKey };
+export { rootKey, rootKeyPrefix, completeRootKey, storeVersion };
diff --git a/web/redux/persist.js b/web/redux/persist.js
--- a/web/redux/persist.js
+++ b/web/redux/persist.js
@@ -46,7 +46,7 @@
   handleReduxMigrationFailure,
   persistWhitelist,
 } from './handle-redux-migration-failure.js';
-import { rootKey, rootKeyPrefix } from './persist-constants.js';
+import { rootKey, rootKeyPrefix, storeVersion } from './persist-constants.js';
 import type { AppState } from './redux-setup.js';
 import { unshimClientDB } from './unshim-utils.js';
 import { authoritativeKeyserverID } from '../authoritative-keyserver.js';
@@ -523,7 +523,7 @@
     migrations,
     migrateStorageToSQLite,
   ): any),
-  version: 75,
+  version: storeVersion,
   transforms: [messageStoreMessagesBlocklistTransform, keyserverStoreTransform],
 };
 
diff --git a/web/shared-worker/worker/backup.js b/web/shared-worker/worker/backup.js
--- a/web/shared-worker/worker/backup.js
+++ b/web/shared-worker/worker/backup.js
@@ -3,13 +3,17 @@
 import backupService from 'lib/facts/backup-service.js';
 import { decryptCommon } from 'lib/media/aes-crypto-utils-common.js';
 import type { AuthMetadata } from 'lib/shared/identity-client-context.js';
+import { syncedMetadataNames } from 'lib/types/synced-metadata-types.js';
 
 import { getProcessingStoreOpsExceptionMessage } from './process-operations.js';
 import {
   BackupClient,
   RequestedData,
 } from '../../backup-client-wasm/wasm/backup-client-wasm.js';
-import { completeRootKey } from '../../redux/persist-constants.js';
+import {
+  completeRootKey,
+  storeVersion,
+} from '../../redux/persist-constants.js';
 import type { EmscriptenModule } from '../types/module.js';
 import type { SQLiteQueryExecutor } from '../types/sqlite-query-executor.js';
 import { COMM_SQLITE_BACKUP_RESTORE_DATABASE_PATH } from '../utils/constants.js';
@@ -55,6 +59,13 @@
       backupDataKey,
     );
 
+    const backupVersion = sqliteQueryExecutor
+      .getAllSyncedMetadata()
+      .find(entry => entry.name === syncedMetadataNames.DB_VERSION)?.data;
+    if (!backupVersion || parseInt(backupVersion) > (storeVersion ?? 0)) {
+      throw new Error(`Incompatible backup version ${backupVersion ?? -1}`);
+    }
+
     sqliteQueryExecutor.setPersistStorageItem(
       completeRootKey,
       reduxPersistData,