diff --git a/packages/nocodb/src/version-upgrader/upgraders/0225002_ncDatasourceDecrypt.ts b/packages/nocodb/src/version-upgrader/upgraders/0225002_ncDatasourceDecrypt.ts
index bb53e2884d..0d69bfcfe1 100644
--- a/packages/nocodb/src/version-upgrader/upgraders/0225002_ncDatasourceDecrypt.ts
+++ b/packages/nocodb/src/version-upgrader/upgraders/0225002_ncDatasourceDecrypt.ts
@@ -63,7 +63,7 @@ export default async function ({ ncMeta }: NcUpgraderCtx) {
   logger.log('Starting decryption of sources and integrations');
 
   let encryptionKey = process.env.NC_AUTH_JWT_SECRET;
-  let fallbackEncryptionKey: string = null;
+  let fallbackEncryptionKey: string | null = null;
 
   const encryptionKeyFromMeta = (
     await ncMeta.metaGet(RootScopes.ROOT, RootScopes.ROOT, MetaTable.STORE, {